Some more pictures. There's an interesting hole in the chainguard that looks like it could be factory but serves no obvious purpose. No date on the crank or marks on the hardware but the bearing cups look like black-outs. I'm stumped when it comes to the weld on the down tube, it looks very neat, almost like it was done with an ox-acetylene torch, but I thought they were arc welding by this point, not gas welding. There's no bump or protrusion on the inside of the bottom bracket, but there is a hole, while there are no holes where the chain stays are welded. The chain stay welds aren't as neat, either. The mark on the back side of the crank looks like some kind of symbol followed by "9620-A", whatever that means.
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