Gemini SST80

Sorry I am new paying member and didnt read instructions for posting.I hope this is the right spot.I was wondering if anyone knows how to date a Gemini SST80 I have two that I made one complete one out of and the serial # is M8-02191. VMX magazine states 10,000 units were made from 69 to 73. Any help is appreciated.
Thanks runs pretty well. Had it completely apart.Trans main shaft was bent from kicker stop breaking.The engine and frame # match but its two bikes made into one.Cleaned alot of rust off.Painted wheels, used bigger carb off later parts bike,pretty happy for 40 year old bike.Is your Gemini complete and running?