Good evening,
this is my very first thread on this truly lovely forum. I did use the search function but still feel as if asking the coming quesitons is appropriate. (Hope it is)

I am the proud owner of a Speedmaster Professional with the notorious Lemania 2310/ Omega 321 caliber. Probably the watch that fascinates me the most.
Said watch has an unknown histroy and was bought from an independent dealer that was more into Langes and didn't know much about it.
Serial-No. is 2495xxxx which should make it a 145.012. The owner before me had it serviced at Omega; dial is superluminated with an applied logo; hands and bezel are new too. The steel bracelet is OEM (an 1171 with 633(?) endlinks; wasn't produced until the 70s but is still available from Omega for old pieces afaik) - I assume it was changed during the restauration/service.
It does have an aftermarket caseback I love but came with a grey omega box with a hippocampus caseback and metal shield. Ref.-No. of the caseback is 145.0012 -> so it should be a service caseback?
I see this watch as an old piece that was serviced and fully restored to a new standart. Things that were worn were probably changed, but it keeps great time, looks like a new watch (on a strap) and me seeing that movement makes me happy.

My watch kissed the floor two days ago and the crystal (with omega logo in the middle) is now cracked. Furthermore, the hour hand is not alligned properly anymore; when setting the minute hand to the full hour, the hour hand is 5 minutes past. This has happened after a drop one year ago as well and was fixed by taking the hands off and putting them back on- no big deal. All other hands are in positon; I find it werid that for the second time, it is just the hour hand that is "loose".


I don't want this watch to be sent to Omega as a service would be too expensive for what's to be done and wouldn't be neccessary. It keeps time very well and was serviced by a watchmaker before I bought it in 2018 and checked after the frist drop which didn't crack the glass.
I found a local watchmaker that would change the glas for me if I provide it. So I went on Ebay and bought an Omega glas, but it did not come with a "tension ring".
I cannot use it like this, can I? (Is it meant to be sold without the ring, is it usable?)
Can I use the tension ring of my broken glas (pull it out and place it into the non-broken crystal)?
Will it fit? I am concerned that I don't know weather the case is from the 60s and therefore a 145.102 case or a service case (hence the service caseback). I do know that service cases exist but don't know if they have a serialNo between the lugs like new Omegas. Some crystals are sold for specific speedmaster (pro) references; does it really matter that much? What would you do?

Thank you for your time to read. Kind regards,
M

 

The crystal for this case is the same as the modern Speedy Pro, so 063PW5139.

The crystals are sold with tension rings by Omega, so whoever sold one without, likely removed it. The tension ring can be swapped between crystals.

Cheers, Al