Text and photos by Jim Breazeale
[Editor: The "type" numbers shown are not mean to indicate an official factory designation, they are just a way to give a label to the various seat hinge types used over the years in the B and C cars. Scroll down the page to see all the photos.]
1955-57, 1958T2, 1959 T2, 1960 T5
"TYPE 3" 356B T5 (60/61 year model cars) Date stamps in my pile 4/60,5/60,11/60,3/61. NOTE: Seat back adjuster lever and the improved covers on the back side.
"TYPE 4" 356B T6 (62 and early 63) Note: Added seatback restraint (the hook at the bottom of the hinge). This feature was on both passenger and driver side seats and eliminated (what were they thinking?) on the driver's side seat in the late T6Bs. I have only 1 seat hinge with the restraint feature with a date stamp 7/61. It is my belief that date stamps ceased to be added at that time.
"TYPE 5" 1964 (year model) 356C NOTE: Same as late 63 356B (no restraint on driver's seat) except the the small rivets on the outside were eliminated.
"TYPE 6" 1965 (year model) 356C NOTE: Completely redesigned hinges. No restraint on the driver's side seat hinge. Beige/grey plastic covers over the springs on the back. This hinge was used for a number of years later in 911 and 912s with minor changes.
All of these hinges have crossover tubes that connect the hinges together on each seat. There are many different kinds and I don't have examples of each type to photograph.
Comment by Brad Ripley: Most, if not all, seat recliners had date stamps, either punched in with dies or, as John Chatley mentions, put on with a rubber ink stamp. See Registry article photo (PDF file). Of course, the ink stamp may have been removed by solvent and certainly gone in any re-plating process.
(back to Jim) The date stamps seem to be random, or as Brad suggests, that they just rub off. I kind of doubt that, though. They are usually done in blue ink and in spots that are next to impossible to see and hidden from sunlight, unless you take the hinges off the seats. They quit stamping (in the metal) a date stamp in the seat hinges in the 2nd 2/3s of 1961, right about the time they started installing seat back restraint mechanisms, as far as I can tell. My "research" is pretty unscientific.