I forgot to take pictures of the headtube before mocking the frame up on some old wheels, but here's a pic of the bottom bracket.
Looks like you have butyl tubes. If you buy TPU tubes on aliX, should cost you <10usd for a pair, and that should save you 5-7W, something like that, at every moment you're out riding. Which is a lot.
It's quantified on bicycle rolling resistance website if you want to have a look.