Indeed, the key question here is whether the 3861 will be NASA certified.
The Gold Apollo 11 50th Speedy LE does not state "FLIGHT QUALIFIED BY NASA FOR ALL SPACE MISSIONS", just "FIRST WATCH WORN ON THE MOON". Why would Omega get qualification for the 3861 for a 7K LE run on a pseudo two-tone Speedy and not for their flagship PM "moonshine gold"Apollo 11 50th LE?
IF the 3861 is certified in the future and IF (a massive galaxy sized IF) Omega manage to persuade somehow NASA to choose the 3861 Speedmaster on the upcoming Mars mission...well then I think the 3861 Speedy LEs will have significant demand. On the other hand, if the 3861 Speedy does not gain NASA certification, I think the 1861 watches will still retain value as the last Speedmaster range certified for Space/EVA.
To be honest, I really can't see a technical reason for NASA continuing to use mechanical hand-wound Speedmasters in space missions vs more modern technology in the 21st century. Why would a Government publicly funded agency bother to go through all the certification effort for clearly obsolete technology, even if Omega were to cover the cost for the 3861?