I replaced the old caps with the black LCF Custom finned carb caps that Brent sells. They come with nice SS allen head screws as well.
If I recall, you can also access/replace your needles via the cap as well. Is that correct Z? I'm thinking of trying Thruxton needles this summer.

Blue/White 2007 TBA, Thruxton needles, Unifilter, AI removed, Polaris Bellmouth, Bubs, Nology Coils/wires, Lightbar, Ricor Intiminators, Hagon Nitros, Tall Sissy Bar w/luggage rack, Dart flyscreen & Lowers. 130 Mains, TrueGel Battery MG12-BS.