It's on the body, on a small stainless tag spot welded to the driver door hinge pillar. Or maybe an aluminum tag screwed there. Chevys and Pontiacs are very similar, they had a screwed on tag 49-50 and spot welded 51-52. and no number on the frame.
Nothing on the frame but if its got a stock engine there should be a number located on left front corner of block toward the top . Engine an serial number will be the same.
i bought a 1949 pontiac conv project just wanted to know if they still have in on the same frame or not thanks
I was going to suggest checking the frame, my 46 Olds has it stamped on top front of LH (Drivers side) rail and on top rear of frame above bumper irons. Very feint.