A little Yondu fin theory because I can
When he loses his actual crest fin, the big prototype fin is the first one he has as a replacement. It doesn’t work perfectly and over the years its condition deteriorates. So he starts working on a replacement. It works better but it’s smaller, which he doesn’t really like, but it’s better than a defective fin. He keeps the old one in his drawer and forgets about it.
But when they escape after the mutiny, Rocket is able to not only rewire it and install it, but he actually fixes some of its previous issues and makes it better. The big fin isn’t the same as his natural crest, but it’s as close as he’s going to get. Dying with that fin is a strange but comforting honor. When they burn his body, he still wears it, and it burns with him.
But Rocket, who fixed up the arrow, managed to replicate the fin as well, and that’s what we see Kraglin wearing in the credits scene. I think eventually Krags might ask Rocket to find a way to permanently attach it to him, to honor Yondu.