The LR3 beta wasn’t much different from the released model. It changed from having the same skate wheels as the LR2 to just the bearing wheels (mine still has the skate wheels.) The first model was proposed to use 1/2" conduit as X and Y rails both. I am still using the 1/2" conduit Y rail, but the X rails weren’t rigid enough, so it was updated to the same choices as the Primo, 3/4" conduit, 25mm tube and 25.4mm tube.
Anyway, a pretty quick process.
The LR4 has undergone larger changes than that between iterations, though tube size hasn’t been one of them. Large scale re-printing has been a big one.
Pretty sure Ryan feels that it’s close, but the beta team is a bit of a fractious and vexatious lot, and it was “close” in the last 2 iterations.
A third release candidate is in progress, but only Ryan has it so far… or at least I haven’t seen it yet.