Replacing requires drilling out the rivets on the tang (4 rivets), on the two swivel padeyes for the main sheet attachment (2 rivets each), and the boom end fitting (5 rivets-I think). Surprisingly, with the right sized bit, the rivets came out a lot faster than I thought. Everything should then slide right out of the track. The boom-end fitting may require a few taps with a hammer to get off and back on. With the fitting off, I found this a good opportunity to clean/check the mysterious outhaul blocks. I would recommend you do this on land to prevent losing any parts and to be able to stand the boom vertically to retrieve any sheered rivets.
Of course, all of this requires you to rivet things back into place, which actually tends to go quite quickly. The various part numbers are listed below, including a much more powerful rivet gun than the older style.
Tang piece (scroll down to part NB2-16-16): https://www.rigrite.com/Spars/Sparcraft ... 0_boom.php