I seem to recall complaints about some early DVDs, similarly sourced, that were encoded as interlaced.
(There are two ways of encoding NTSC MPEG-2 video for DVD: 23.976 fps progressive or 29.97 fps interlaced. For film material the first way is much better, for reasons I won't go into here.)
I wouldn't put it past Lucasfilm to take the easy option and just release the DVDs as interlaced. If this is the case, then I'm glad I live in a PAL country!
I hope September proves my concern to be unfounded.
Guidelines for post content and general behaviour: read announcement here
Max. allowable image sizes in signatures: reminder here