F2 film counter, stay put or count up on rewind?

I have two F2 bodies, one in the 76xxxx serial number range and the

other in the 78xxxx range. When rewinding the film, the film counter

on the 76 body stays put, but the counter on the 78 body continues to

count upwards 'til it reaches about 32 or so (I've only used 24 exp

film, so I have no idea what would happen if I loaded a 36).

Both bodies work fine so I'm not concerned about one body being

defective, but did Nikon make a change to the counter mechanism

somewhere between these two serial numbers?