The later round bolts (yours) had a hole about midway along on the bottom and came with the late type extractor, ejector, and firing pin. If the parts in your bolt are the earlier designs, then they may have been changed over. I have a new .U. round bolt that I bought as a
bare bolt in green colored wrap 17 years ago at a gun show. I think it was originally complete and someone removed the parts and wrapped it back up. I've never seen any evidence that Underwood packed the post war bolts in boxes for shipping, but they may have. I do have some pics I found in 2011 of their boxed complete bolts.
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I've never changed a barrel band, but have heard R&R on some front sights can be a real challenge. Original (Bayonet) Type 3 bands can be reasonably priced, but original Type 1 and Type 2 bands can run hundreds of dollars.
Now, I'm curious if you already had a bolt tool on hand or did you "pull it off" without one? :thup: - Bob