At first this seemed awfully steep, but then I checked and I see you have the certificate of authenticity and the original wooden box it came in so I think you're may be OK with your asking price. I also found a few places that are selling these for about the $150.00 you're asking.
Like everything, the rarer they get, the higher the value. I don't know how you'd find out how many were made, but that could help your cause.
AND like everything else, the value is worth what it finally sells for.
This could be a valuable addition to a serious collector with 50th Anniversary Memorabilia.
Chuck M