At the time it was felt there was no need as it was not thought there would be any more movies made.There's actually,and perhaps more surprisingly,very little from ESB in the archives also.ROTJ is well represented in the archives though.If anyone is interested in a tour video of the LFL archive I have a link somewhere I could find and post?Some pretty amazing stuff in there.Also for those interested in this sort of thing:
Star Wars Collector's Archive Props Page
Some great stuff and contributions from collectors including the ANH Death Star model.
And dont forget,ahem,
MY SITE!!!!lol