Hi I think the genuine part will fix it after market parts although look the same quite often are not. Consider the crispness of the edges of the pattern part are they sharp if not that is likely the problem sliding over the pin not along it.
not difficult if you have some experience, no experience i wouldnt try it...check for broken teeth on hour/min wheels and clutch/ratchet wheels. If any are broken you need to source a new one. and iam not familiar with this watch but is there a sub second hand or a center second hand? if so check the second hand and make sure it not binding up somewhere this could explain what i like to call the "ghost escapement" when power is applied to balance but then train gets jammed causing the escape wheel not to spin. there are other causes of this but i would rule those out since you now say its running fine and keeping accurate time.
Hi Mick I have attached a service sheet for you. If its a front loader it will have a split stem (two parts) and removal requires a straight pull on the stem to separate the two halves, and remove the glass you either have to remove the bezel ring and the glass or to have to pressurise the watch case and blow out the glass, depends on the case type. I have also attached some further info hopefully usefull
7197_Omega 565.0008 BA Case (3).pdf
Hi as stated its a dollar watch. It is what is known as a fashion watch, purely for show probably a miyota 2030/35movement. Take Andys advice and have a coffee. 20 yrs ago you could get one of these free with 4gallons of petrol (gas) in the UK,