It's the same part number for all series, but it's one year only, Buick only, and has been obsolete with no supercession nor aftermarket replacement for a good twenty years. I think it was Delco D1439A, GM 1116698. The lock cylinder is still available; it's the switch and its arrangement of terminals that's scarce. Patrick
Sorry to revive a dead post, but I'm in need of one too if anyone has the 1116698. 8 pin switch, mine will start, but it wont shut off.