Those look like solid rivets. If so you would have to drill or grind the head off one side and use a pin punch of the appropriate diameter to knock the rest of the rivet out. You could pop rivet them back into the new piece or use a solid pin of the correct diameter made of aluminum or brass and use a steel backer bar or anvil and either an air hammer (fast but tricky) or a hammer and a larger diameter punch to mushroom the ends of the pins.
Yes, need to file off the inside end of the pin, then knock it out. You then won't have enough material on the end to peen over and put back. Will need to make a new pin with excess on end for peening. hmmmm...if you only knew someone with a lathe....