I would not be surprised if more of the later BT60 based Gemini-Titan kits were produced in the two years it existed than the 7 years the original K21 did, which would make the collectible value lower anyway.
I know the newer one shows up on ebay FAR more often than the early one.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !