Is it tinted? I'm not sure they tinted back then but tinting could break the symmetry in possibly an insignificant way. The fit would be the same, though.
When I got my '48, all the flat glass was cracked. I put in new fully tinted glass for the windshield (no tinted band on top) and clear glass in the doors and rear at a glass shop. It didn't cost that much but it was 25 years ago. The corner windows had the only good glass, thank goodness.
1948 3/4-Ton 5-Window Flatbed Chevrolet 34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.