[Blas]

There is nothing wrong with an earlier SPF car. The major changes were related to addition of dropped foot boxes, the rims, cowl height, the front brakes, wiring harness version. If you are not 6'-6" tall, no problem. Drive the car and see if you fit. The rims are probably the Trigo's and not the early steel rims with fake KO's - Trigo's are what you really want... And the SPF front brakes have just been upgraded 2 or 3 times over the years...The engine's in the car so you don't care about a taller cowl height like on the newer cars. Convertible top has been updated but of little real concern. The wiring harness has just evolved of time, no big deal. Best thing, it probably has some stone chips here and there so you can sleep soundly at night not worrying about getting one. Go look at the car and drive it...If it runs strong and looks to have been taken car of...go for it if the price is right.
FWIW: I myself prefer an older chassis with the lower cowl.