[joedoh]

looks like 2 hots and a ground, which might be what you meant, just got mixed up.

either way, looks like a standard 1157 bulb with two filaments, the two wires that attach to the base are the hots, one wire for park light (the dim) and one wire for brake turn (the bright). that bulb grounds through the metal base, looks like a pot metal casting. that spade connector is an additional ground, usually just screwing that pot metal base to the sheetmetal is enough ground, which is why the other side doesnt have it, but if they give you the extra, might as well use it! take it right to the frame with a nice star washer.

so yes, you have (and really most all chevys have) the shared turn/brake bulb.