Ok, an update on my attempt to 'upgrade' my original 40th anniversary RotJ Luke:
don't try this, guys! I almost ruined a perfectly mint HT figure in what turned out to be a complete failure. I bought the new Deluxe black outfit and one of the Deluxe heads, thinking I could just use them on the older figure. But, turns out there are several incompatibilities and snags that make this less straightforward than it seems at first. First of all, the 40th anniversary version is basically sewn into his black suit. So taking it off requires some tearing of the stitching that holds the front panel of his suit down, or it's impossible to remove. Also, while the underlying HT's body shape is more or less the same on both, the Deluxe one has a different size neck peg! The interchangeable heads therefore likewise have different size holes at the bottom for said peg, making it impossible to use the new head on the old Luke body. This is bizarre to me, because the old Luke head also has the swappable hairstyle, so it would seem they made it with the eventual Deluxe one in mind, but the sizes are just not the same at all. The new headsculpts have longer necks as well, so even using the old head with the new outfit looks weird due to the padding differences. I tried all possible combinations, and it's just not an easy enough upgrade to make it worth it. Now I have a ripped/torn 40th anniversary outfit, which I had to mend and put back onto the old body, which is not only upsetting but was also a huge pain in the @ss. I'm mad at myself for even attempting it.
My plan now is to just permanently leave the old 40th anniversary edition as the cloaked version, and try to get the rest of the parts to make the 'upgraded' Deluxe RotJ Luke from scratch instead. Due to my increasing lack of display space, I actually didn't
want two separate RotJ Luke's, or I would have just done this in the first place.
Sigh. Rant over. Just wanted to mention this in case anyone else was thinking of attempting to do the same stupid thing as me...