They are not proper seacocks. They are not flange mounted and the ball valves may or may not be proper bronze. I am surprised that in 2001 a builder is still using those. Who built that boat?

Put Marelon seacocks, through hulls and tail pieces in and forget about electrolysis and servicing. The only service they need is to be turned every few months and lube them annually with a little salad oil or superlube grease.

I have many original Marelon seacocks in my 1985 boat and they still work fine - some haven't been lubed in years.