My 2006 B323, hull 136, Has yet another type anchor bulb. It is a single-contact Italian OSRAM/Sylvania 5008. T6, .83 amp, 10 watt, EIKO 4-663, 15 mm base, it it is a "BA15S" base. 1.44"long, 125 lumens, same(supposedly) as a 1141 or a 1156 bulb. Lamp(glass) shape B6, which is almost round. .....
After going to West and Fawcetts, Fawcetts had the Hella light, which had the exact same bulb. The search for an LED that will fit continues.