Early SI tach sender

I have an SI replacement rectangular tach sender that is a few years old and missing the instructions for wiring it up. The new ones they sell have different color wires and so far they haven't found any info for me on the older ones. The one I have has four wires; black, white, red, and green. I hate to just ASSume and blow the thing. Anyone know which goes where? I am thinking the "normal"... red to keyed +, black to ground, green to distributor side of coil and white to the brass side of the tach. I have the instructions for the ones they sell now but am wondering if the early ones wired up like the factory one? Studebaker George