1964 4 door originally from CA. in good shape, but not fantastically maintained - This has the early calipers.

Went to swap the MC, but before removing it, checked the bleeder valves to determine that I'd be able to bleed the system after installation. Both calipers have what appears to be the remains of busted bleeder valves. I could try and remove them with an extractor, but figure if the valve busted, my chances aren't great without heat, and would rather spend the time rebuilding another pair, and swap them out

Is there any problem in replacing EARLY 3 pot calipers with LATER 3 pot calipers? The early ones have an external crossover line, and the bleeder valve is on the "top" pointing up - the later version has the bleeder valve on the "top/side" oriented horizontally. Any other things I should look out for?

I'm thinking to also get new lines from the body to the caliper, to avoid the frustration of rusted line breaking on removal.
Anybody have a set of prebent, used, good lines (body to caliper) and calipers from a later setup?