Stains on Omega 3513.53.00 Sapphire Crystal: AR Coated on Outside Side?

Hi. I recently purchased an used Omega Speedmaster Reduced, Reference 3513.53.00 (SN 5990788X) which was issued only on 1996 for the Japanese market:



The watch is in pretty good conditions but have noticed what seems to be faint water spots / stains on the sapphire crystal (very hard to capture in a picture, only noticeable if you hold the watch up at an angle against some lighting; slightly visible above about 12 o'clock. No actual scratches are felt on the surface). I read in the forums that this may be deterioration on the anti reflective coating of sapphire crystal but am not sure if this particular model comes with AR on both sides or only in the inner side. This is what I could found from OFREI:



Given how old the watch is (18 years) is hard to get the actual specs from Omega. The AJTT shows the watch with leather band on page 632 (3513.53.00) and 661 but does not specifies anything about the crystal coating. I was able to get from Omega the specs on 3513.50.00 (same watch, just different dial ?) and that one is listed as having AR in the inside side only:




So imagine mine has AR coating only on the inside. Can someone confirm this?

If it does have AR only on the inner side of the crystal, what can be used to clean the outer side of the sapphire crystal?

Thanks,

Francisco

i do have the same problem in my Tag Heuer Aquaracer, i think you can try to apply GS27 scratch remover wax for cars... and it is effective... some other car wax and even turtle wax can't remove the stain on my wATCH BUT WHEN i TRIED IT IT IS VERY EFFECTIVE IN JUST ONE APPLICATION.

Thanks to all. I tried the Cape code without luck, so ended up buying a new sapphire crystal, which will get installed when I service the watch (most likely early next year)