If it's worth the investment on your part for the car, then it's worth the $$$ for the PHS documents. A lot of funky things can happen during 48 years of ownership.
Two things to check on that LH traction bar - if there is NO Riv-Nut into the inside face of the LH rear frame rail, then it did not leave the factory with both bars and probably did not leave the factory as a stick car. Also - there would be two studs through the rear floor pan under the seat that would be hard to either make go away or appear.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI