Google spyderco collectors club.
This^
There is a Spyderco "Collectors Club" and, if you are a member, it will imprint your Collector# on each knife that you receive.
However, for this privilege, you have to agree to buy a certain # of knives varying from ALL of them (Main, Sprints and Variations) to just Main/Sprints or just Main but that could cost you A LOT of coin depending on how many knives are being issued by the company. That's why you see so many #'d knives being resold here on the Exchange and in other 2ndary markets soon after a new release.
Membership in the Collector's Club is limited to 200. So, a knife can be numbered from 1-200 BUT this doesn't mean that there are actually 200 members in the Collectors Club.
When I inquired about the club back in Dec 2018, I was told that the club was operating under the same rules since 2009 and they sent me a list of the "available" numbers so that I could pick the one I wanted, which means that the # on a knife is irrelevant to it's rarity or your standing on the list. So, don't believe the hype when someone says the # on a Spyderco means it's worth more because it's a low or limited #. It's BS.
The lowest # on the list I received was #18 and the highest was #198. There were 98 available numbers on the list, which means that the Collector's Club was barely 50% subscribed at the time.
So, I chose not to join, even though I could have had #18. LOL!