If your oil pressure switch was not damaged in the accident, then it should not need to be replaced. The oil pressure sensor screws into the block and has a weather tight connector on it. I don't believe there is anything to reset with the oil pressure sensor at least not on my 96 there isn't. Your car is before the OBD II computers, so try disconnecting the battery for about 15 min then try to restart the car. If no luck, call Chevy and see what they say.
1969 Camaro 350, Trickflow heads, ST-10 4spd, Hotchkis suspension, Baer SS brake kit, moser 12bolt