[WFBowen]

Peter
You're right. After reading JT's post I started to remember the driver's side not having the locking function. Here's an old post by Jim Breazeale (who definitely knows his stuff) from a 356 board on the subject:
"A bit of history...................
Porsche provided seat back locks on both seats when they started producing T6s in late 61 (1962 year model cars).
At the same time, they installed a spring loaded "breakaway" inside rear view mirror. Those 2 safety improvements were touted by Porsche in their advertising for the 62 year model cars. For some reason, known only to Porsche, they deleted both of those features early in 1963. Those 2 features reappeared in 1968."
Bill