This was discussed in the Star Wars Poster Collectors group on Facebook, but I thought I'd stick it in here too as it's sometimes hard to find historic information in Facebook groups.
A few years ago, I picked up a rolled Style D from an auction in Japan. It's 27 x 41" and has the "D" in quotes like the normal Studio Style D, however when I compared it to my (bashed up) normal Studio Style D, I noticed a few differences (photos below...any colouring differences more likely bad photos and my normal Style D being bashed up and a bit faded from framing). I had a chat with our resident expert (Undead) and I think we both thought it was perhaps a Japanese fan club or re-release giveaway poster as they have surfaced a few times in Japan and are often rolled, but they don't seem to be found in the US (I can't see Bruce has sold one before, for example). However, a member in the Facebook group recently posted the same poster and asked for authentication help and Stephen Sansweet chipped in to confirm he has one with the same credit block and it came directly from Fox in 1978.
Anyway, not the most interesting post this forum has ever seen, but I thought I'd share here for information/documentation as I'm a bit of a Star Wars nerd and find these little details interesting and perhaps it'll help someone down the line.
Differences in font and sizing (normal Studio Style D on the bottom):
Differences in stars, noticeable in placement of star next to/under the third dot in the ellipsis (normal Studio Style D on the bottom):
Differences in 20th Century Fox logo (normal Studio Style D on the bottom):
Differences in Cast font in credit block (normal Studio Style D on the bottom):
Similarity in Style "D" formatting, with minor font difference (normal Studio Style D on the bottom):