Just for giggles I'll make a few comments to help understand the nuances of the 68's. The partial vin may be stamped on the engine and automatic transmission by the oil sender unit (this you already confirmed), with a 4-speed also getting a partial vin on the 4-speeds side raised pad (but not always). The fender tag S.O. number (6 numbers) will be stamped on the radiator support frame (top drivers side) and also stamped on the drivers side trunk lid jam (under the rubber). The only way to definitely tie the engine and transmission to the car (fender tag and radiator support and trunk stamping) is through the buildsheet.

Dan