I stand corrected...
After checking with a local VE here, he and another VE confirmed that 97.505(4) does state that a currently licensed Technician who previously held a Technician Class license prior to March 21, 1987 that is expired
can show proof of the previous license in order to get credit for the General Element 3 exam. This will require unobjectionable proof that the person did in fact have a Technician license issued before March 21, 1987, and that the previous license is expired (wasn't renewed.)
Sorry about the confusion in my first post to this thread. I've learned something new and glad I could find out and pass along the correct information. Thanks "Token" for suggesting I had it wrong
So to the OP "oldcallsign" good luck in finding the documentation you're needing! Hopefully you can track it down and get upgraded to General Class.
73's!