The problem with chroming the seat lug and BB shell is the unfortunate fact that they're both impossible to clean up scratches and file marks to the nth degree required for chrome. Every little stray file mark would show up, unlike after a couple coats of primer and then the topcoat. At least, that's the way it was explained to me when I requested chrome in those areas when speccing my first custom.

However, I once saw a way around it on one of Jerry Duran's frames: stainless steel Henry James lugs and BB shells. As he points out, chrome plating has microscopic cracks in it, and humidity/temperature changes can result in moisture getting under the plating via those cracks. Over a period of time, the area in question can be weakened.

Not what I'd want at my BB shell!

DD