As I took it from the Ebay ad, you would have to buy all 4 regulators (for a complete car) but only one, the one for the left rear, would match what you want. You could then re-sell the LF, RF, and RR regulators if you had no use for them. Are you looking for a regulator(s) for something OTHER than a sedan, like a Hardtop or convertible with the hydraulic lifts, and they are different from a manual crank regulator?? Otherwise, somehow I'm just not getting your point, and I'm now confused. If these are for a 49-50, and it crosses with a 51 Fraser which was still using the same body, how is it different?