I'm looking at replacing the stereo pad on my '70 SS with the proper single speaker pad. I found one and I'm not sure if its a repop or original. On the inside of the pad it reads as follows 1972, 9751658-std, 9751784-stereo. Can anyone help decipher these codes.

1972 is the model year application but 70-72 use the same pad. the other numbers are the GM part numbers for single speaker (std) and stereo. Both numbers are on there because the same inside structure was used. The difference is obvious otherwise, stereo has speaker holes at each end whereas the stab=ndard has speaker holes in the middle.