The bezel is screwed down, I read it on another forum, the crystal is a flat mineral and is flush with the bezel. I was thinking of pulling the stem out and do the syringe thing but I don't think it's gonna work.
I will post Caseback pics later.
I don’t want to burst your bubble and you asked for my view. Unless you have a lot of experience, it will be extremely hard to pull this off. It looks good on paper but to get it just right I don’t think it will work. Silver solder is quite soft and you will not have the space for the solder to have a solid grip.
Why don’t you put it to the side and keep checking for a spare stem.