I have 77 lemans with the can am package how can tell what is sequence number it is?

that's the sequence number , the last 6 . what in particular are you looking for ?

If its authentic Can Am, the VIN will start with 2F37 Z 7P (the "Z" signifies the W72 400 engine, and will be replaced with a "K" if the car has the alternate Olds 403 engine). As GTOMike correctly states, the last 6 digits are the assembly line sequence. All assembly sequences started with "100001" regardless of which plant produced the car. That means that your car would be car number 216232 to roll off that particular plant's production line. This would include ALL models produced, so it's of limited value on it's own. To find out how many Can Ams rolled off before yours requires a bit more work. Your best source for the facts is going to be PHS. Good luck, it's an awesome car, keep it all Pontiac!