. Indeed... Omega Speedmasters stay attached to Orlan spacesuits, check the left forearm of each EVA-unit: Photo: NASA - ISS Exp 40 (2014) .
My post was half in jest. Not being a space nerd I don't have an understanding of EVA procedures and processes and I'm pleased to see the great info posted here that explains some of it. BTW: Space nerd isn't meant to be derogatory, it's just a term that came to mind. PS: Not being a "space nerd", I only own one "flown in space" item. A lowly dog clip that was attached to a thin white nylon tether line on a capsule that toured Australia in the 1970s (Gemini IV?). It was looking rather rusty so I replaced it with an identical item from the base stores system. Please don't tell the US Government.
The end pieces are custom made and appear to be the standard now. These straps are also not Velcro but a heavy gauge elastic.
So judging on those recent end-links, that would be the Speedmaster of Yurchikhin's August 2017 spacewalk during ISS 51/52
Highly possible that only the watch was flown and not the strap as seen. I've observed cosmonaut EVAs recently with and without the end pieces seen above. The credit does not mention the strap so I'm thinking just the watch is flown.
I'm sticking with my original theory that the watch was probably part of the MIR crew equipment and brought back by Budarin. Here are some images of STS -71 bringing up Nikolai Budarin to start his MIR 19 mission. He replaces Mir 18 flight engineer Gennadiy M. Strekalov who returns on STS - 71. You can clearly see Strekalov is wearing a Speedmaster on a leather strap, same as the one being sold. Budarin is not seen wearing a Speedmaster in the crew transition photos only wearing a black digital watch so my theory is that the watch Budarin brings back is possibly the one we see Strekalov wearing or another one. There is clear evidence that there was a Speedmaster on a leather strap on MIR 18 and either it was left onboard for MIR 19 to use or there were multiple watches on leather. Either way, Speedmasters on leather straps flew on some MIR missions. Budarin in backrgound in these two.
Strekalov brought back a Speedmaster that was sold by RR Auction in the past. https://www.rrauction.com/past_auction_item.cfm?ID=3277511
Probably the Speedmaster that was featured in the official TM-10 crew portrait ? https://omegaforums.net/threads/hidden-gems-from-the-russian-space-photo-archives.65152/page-2