Thank you @JohnR725 and @Nucejoe for the reference links, I'll make sure to check the ebauche symbols next time before asking.  @praezis I get your point about swapping parts. I haven't done a balance staff replacement and really should learn if I want to get better at this.

Balance complete - Spring and wheel . The staff was replaced by a local watchmaker and he bent the harispring. 

Dr ranfft sees no difference between venus 180, 181 & 182, and  other calibs of same family are highly likely to  fit. @donutdan  Go on to the link below to see all related calibs, of all them you might find one to buy. https://ranfft.org/caliber/10591-Venus-180  A venus movement  is a terrible thing to deprive of TLC. Good luck   

Hi John, I didn‘t adress you or your statement, just grabbed a fitting quote 🙂. Maybe it‘s me, but always getting a bit nervous reading about „parts swapping“. How often did we read here that swapping back and forth didn’t help? Why not try to advance with someone‘s skill and do repair. Frank

Yet another Rolex has landed on my bench — this time a Sea-Dweller, ref. 16600, equipped with the trusty calibre 3135, the same calibre as the last one I worked on. The time and date settings are completely dead. I guess the yoke has slipped out of engagement with the sliding pinion. It remains to be investigated. If that is the case, it certainly makes you wonder how it can occur, considering the outstanding quality of these movements. Perhaps it was subjected to trauma? Perhaps a sloppy assembly of the keyless works? However, it is running very well. A you can see, the maximum delta is seven seconds. The maximum acceptable delta for this movement, as specified by Rolex, is 10 seconds. The average rate fully wound in five positions (crown down, left, up, dial up, and dial down) is 1.8 seconds per day. The rate tolerance as specified by Rolex is -2/+4 s/d. So it's all looking pretty perfect. What's very strange, though, and something I can't get my head around, is that the first time I measured it on my timing machine, fully wound (I could hear the mainspring slip in small steps while being wound), it performed quite poorly. The rates and beat errors were fine, but the horizontal amplitudes were around 235°, and the vertical amplitudes were all below 200°, which is the minimum amplitude as specified by Rolex after 24h. Performing that poorly, being fully wound, I felt it wasn't much use to measure it again after 24h. However, to be thorough, I nevertheless did and to my astonishment, I got the results as seen in the table above - "Fully wound minus 24h (Not Serviced)" - At that point, I decided to give the watch another full wind and take another measurement, and I got the results as seen in the above table - "Fully wound (Not Serviced)". If anyone has any idea about why I got such a poor performance the first time around, please let me know! As can be seen, the oil beneath the cap jewel is noticeably depleting. If it wasn't for the faulty date and time setting, I think this amazing watch could have been left alone for another year or two, but considering it has to be repaired, why not service it as well? Especially considering the funny behaviour in amplitude I described in the previous paragraph. What do you think? All opinions are appreciated, but if one of our much-appreciated pros, such as  @Jon, @JohnR725, @nickelsilver, or @nevenbekriev could weigh in, I'm sure it would be appreciated by many. The fit between the bracelet ends and the lugs was very tight, and I couldn't get the bracelet out by simply pressing the spring bar from one side through the drilled lugs. I'm sure there's an original Rolex tool for it unavailable to enthusiasts, and even so would cost a small fortune. During the years, I've bought a small fortune worth of tools. Some of those tools have been a complete disappointment and a waste of money, such as the spring bar tool in the picture, which I've never used and have been meaning to resell for a long time. However, as I couldn't get the bracelet out, I came to think of it, and cut myself two pieces of brass rod, deburred and polished the ends, bent them and inserted them in the tool. It worked like a charm. I’ve got to say, I’m kind of proud of this little bit of brilliance. If I’d read something like this when I was just starting, eight or nine years ago, I would’ve been super impressed. Especially considering I could barely tell which end of a screwdriver to use back then. Okay, maybe I’m exaggerating a bit, but you get the gist! I just hate it when you can't unscrew the case back by using a rubber ball. Is it really necessary to screw the case back on so hard? It's a sincere question. Maybe it is necessary for a true diver's watch like this Sea-Dweller. Fortunately, I had the right size, a number five Rolex die in my set. Getting the case back off, I had to bring out the "Big Gun". Even so, I had to apply what felt like an insane amount of force. I actually worried the tool might break, and it was not a pleasant experience. So, two thumbs down for the previous repairer, who... ...also decided it was necessary to scratch up the inside of the case back lid, which likely halves its market value. I wouldn't be surprised if the same guy caused the setting problems by being sloppy while assembling the keyless works. We shall see! I’m really looking forward to hearing your thoughts on my questions and musings!