Seamaster 14700 questions - mostly crystal verification

I recently got this at auction at a good price... before the buyers premium. I like the linen dial and the chamfered lugs (although they seem to be very slightly different sizes, but I'm chalking that up to uneven wear or QC).

The crystal, however, has some pretty bad stress fractures and needs to be replaced eventually. It has been difficult for me to determine what crystal I'm looking for. Based on only one website, I think the part is 5140 PZ. Can anyone confirm or correct this? And does anyone know where to find them? They seem to be non-existent now. I'm a little tempted to find a generic crystal, but I've been told the tension ring can scratch the dial, so I'm currently just waiting on something to come up on eBay.

I'm also curious about what is going on with the lume on the minute hand near the center. It's weird to me that the hour hand lume has no such discoloration. It doesn't bother me much at the moment.

Lastly, since I'm here, there are 4-digit numbers lightly engraved on the back of two of the lugs. Anyone know what that's about? I know watchmakers would make marks on case backs and even on movements sometimes. Would some make such marks on the outside of cases? Thankfully they're very hard to see. I only noticed them in pictures at first.

eBay is the way to find them. I bought and replaced a 14700 crystal and the one you posted above is the one you want. It will not be cheap. You will need a good press to install them with the tension ring. The lume just looks old in my opinion.

Before replacing that crystal, I would try to polish it with polywatch. It has the Omega stamp and actually looks to be in pretty good shape if you were to polish it up.

Thanks for the response.

I polished it a little with polywatch but stopped when I realized that most of the imperfections were not scratches but small cracks. They're a little easier to see at a shallow angle.

I just checked my purchase history, PX5140 (gold tension ring) went onto this watch. If you are having trouble finding the stainless tension ring, you can swap the old one into the new crystal.

Good point. There is one on eBay at the moment. Like you said, it's not cheap.

I wonder if anyone here has ever put the tension ring from an Omega crystal onto a generic crystal, and if that reduces the risk of scratching the dial? I'm not really clear on how exactly the generic crystals pose a risk of scratching.

It's dependant on the crystal. Some Omega crystals have a lip for the bezel to be pressed onto. I think the 5140 doesn't have a lip on the outside, but the you risk the tension ring not fitting at the correct depth and digging into the dial. If you could find a generic with the right side wall height it might work.