I had a .861 Pre Moon for several years.....idiot to sell it. They're great watches.... highly recommend.
If I remember the numbers correctly, and if you sold it for $5k like 10 or 15 years ago or so, you lost out on approximately $20-25k gain in value in a decade.
That's what they were worth in 2022. Not sure if prices for pre-moons went down this year like with new steel Rolexes, but since pre-moons are vintage and rare, probably not.
Edit: Nevermind. I didn't catch the Cal. 861. Those aren't as crazy expensive as the older references with the 321.