Is that not because an FM transmitter designed for North American use operates with different increments to an European one? - I can't remember the technicalities.
It could be, but the numbers on the transmitter definitely matched the numbers displayed on the radio. I also don't remember friends of the family reporting any troubles with car stereos they bought here in Canada on vacation and took back home with them (mostly in the 80's).
I actually meant to look this up when I got back last year, but it completely slipped my mind. At least we were able to return the FM transmitter for a refund.