I'm trying to confirm rightly or wrongly, that the Hartford London Navies were made on London factory plant shipped back to the US and continued serial numbers from the end of London production?

I can see a continuation of London manufacture serial numbers might make sense (from a UKicon importing and sales perspective), but surely they would just use existing Hartford plant to build them?

My example seems to have completely standard Hartford manufacturing components..

I've always thought that unused London parts were just randomly employed in general 1851 Navy manufacture until all used up.