It has gotten to be very difficult. After I purchased my 69 RS back in Nov 1991, I began the process of tracing its history. At the time I lived in Baton Rouge, LA and traced the car back through 3 previous owners by going to the DMV in Louisiana, Mississippi, and Pennsylvania. Was able to trace it back to a person in Chambersburg, PA who owned the car from April 1983 - Dec 1985. Couldn't go back any further as the PA DMV told me that their records, at that time, didn't go back any further. That previous records had been lost due to some occurrence, a fire I believe. In any event, I realize this doesn't help your effort any, but like your PA title, where you had a F indicated, mine had a P which indicated that the car was at one time registered to a police department. I've always wondered what that was all about. Hard to understand why a police department would titale a 69 RS. In any event, one of those little historical items lost to time.
I also tried a VIN / insurance history check through someone that I knew in the local police department. Nothing on my car showed up. However, a friend of mine, who owned a '67 vette at the time, was able to find out through the VIN / insurance check the original date his car was titled, where it was originally titiled as well as the original GM delaership zone in which the car was sold. If you know someone who would be willing to run this for you, you might get lucky. My understanding is that this is not something that police depts would normally want to do.
Good luck on your search.