I shot in a Highpower Match this last weekend and the shooter next to me was having FTE's on every shot during the standing slow fire.  Every case was staying inside the upper and rattling around.  He took an alibi and removed the bolt carrier group from the upper.  Upon inspection it was found that the bolt was installed 180 degrees out of alignment so that the extractor was on the inboard side of the receiver!  Every case was being ejected INTO the receiver.  After disassembling the bolt from the carrier, I told him to try inserting the cam pin from both sides into the bolt.  It when in from both sides!  It had a slip fit going in the wrong side but did not require any extra force.  I told him that the bolt was out of spec and that it needed work.  Can he just peen the side of the bolt to prevent the cam pin from going in the wrong way or should he toss it?

Bolts are hard, bolts aren't even supposed to be stamped. Doubtful that the cam pin hole could be swaged after the part is carburized.

He can't remember to put the extractor on the outside of the carrier?

I have seen a few bolts that lacked the bottom peen of the cam channel.  It's not the end of the world; you just have to remember to check the extractor position during install.

The peen was a design addition to allow solders to strip, clean, and re-assemble the parts in total darkness.  Fact, the peen was added to keep even the simplest (read idiot) from not checking the bolt by feeling the alignment of the extractor and installing it wrong. The peen has no function regarding the function of the rifle, it’s just there for the simpleton behind the trigger to install the bolt back in correctly.

FYI: On the M-60E3, parts on the bolt/carrier were changed to keep the guys from installing parts backwards and jamming the rifle. The revision was for the same reason that the bolt was penned, and like the peening of the bolt on a M-16, has no function on the operation of the rifle.