Antenna location, my 46 is on driver's side, check out photos in gallery, Jim Merritt's 46.
I believe the holes were there when I got the old truck, so should be close. Just make it look right, centered and possibly a slight slant aft.

It's easier to get forgiveness than permission!
1946 1/2-Ton Chevy
1953 Chevy 3/4-ton Factory Stakebed