Oldskool,
Really all you have to go with is the history gathered by members of this forum. So the story goes; all of the original documentation was destroyed by the last owners of the corporation. It's pretty typical it seems; they didn't know what they had or cared about preserving the legacy of the brand. So your HIN indicates May 1967 as the build date; assuming the numbers are original. Suffice it to say your hull can only be a '66-'71 vintage anyway. '72 of course was the first year of the 12 degree 22-2 and the complete redesign. So read through all of the available info in the forum archives and you may have to live with that. You can be happy with the fact that you own the boat that started it all; the flatback 22-2 and you have a diver model which is very cool. You will come to fork in the road come rebuild time; assuming that is the ultimate plan to restore to original with new materials or customize as many do or a variant of both. In the case of my '73 that is still completely original and functional; I want to do a restoration and get that boat as close to the day it was popped out of the mold with some very mild customizing mainly dealing with the rigging trough and associated self bailing issues that simply won't work with today's heavier outboards. These boats are head turners to this day and will strike up conversations with people who aren't even Aquasport enthusiasts.