Help Finding Frame VIN Location 58 Impala

I'm trying to find where on the frame the VIN stamping would be on a 1958 Chevy Impala. We've been sandblasting and scraping away at the frame, but just dont know where it would be.

Anyone know where we would look?

I'd also like to know if '41 chevy coupes even had frame stampings, and if they do, where would they be?

Thanks for any help.

Sorry for the double post, not sure which forum to post it in.

The 58 frame may not have a vin, nor the 41, look on the top of the rails on the 58, maybe.