I'm puzzled. I thought the whole point behind rolling-code keyless entry devices was that a single capture won't reveal the current state of the engine in the transmitter.
Yet, the other day I had occasion to program a new remote to my wife's car - or to be accurate, to program the car to recognize the remote - and I find that the programming mode involves a "secret" sequence to get the car into a listening mode, and then a single button press on each remote to be used with that vehicle.
I can't identify the microcontroller - it's an unmarked 8-pin part - but an older version of the same series remote control has two parts (both Microchip): a 24AA01I/SN 128x8 EEPROM, and an 18-pin SOIC marked "150318-1 R54A04IS0001," date code 9751CAN, which I guess is a PIC16CR54.
Is it possible this type of remote just transmits a static serial number along with the button code? I thought all reasonably modern vehicles used rolling-code systems (this is a '98 model year).