I have the original build sheet and owner protection plan card for a 1967 GS 400. The car was originally sold to Joseph Castronove, 2167 Alter, Detroit, Michigan 48215. VIN 446177H242879 If this is your car, I will send you the documentation.
Cool that it had the Am Fm. Did a quick search and he might have passed away in 2006. His car may still be out there.
That's my old car. I bought it from the Strubes out in Colorado, and drove it back to Michigan in 1992. Restored, raced, showed it, sold it. I was in contact with Joe and Pat(wife)Castronova back at that time. I sold the car to a guy on East Coast who was a flipper, who in turn sold it at auction, it went to a dealership in Virginia, then in last I knew it went far west, like Washington state. I pulled the race engine, sold it to Larry Gibson, put the tired 400 back in it, sold the weld drag stars, and put a set of 14" rally wheels on it, and sent it. I changed color to a very dark plum color, I believe it was called Dark Rosewood Pearlcoat.