'51 Frame Curiosity Question

[bwilli2]

While tearing down my truck, I pulled off the re-located steering box and noticed that there is a slight bulge in one of the bolt holes. It's very symmetrical and smooth. I suspect it's a result of the way they relocated the steering box, that bolt likely had the most load on it. But it's so even, it could have been stock.

I don't have another frame for comparison, but I'm curious, is this 'factory' or not?

Not critical, just curious.