It's pretty clearly an Alliance uniform just by looking at it. It exists in the lineage of these guys:
and these guys:
[IMG]http://i925.photobucket.com/albums/ad93/haplotk114/YavinOfficer.png[/IMG]
Etc. Even the insignia is very reminiscent of the ANH/ESB rank insignias.
I've always hated the ROTJ design retcon that resulted in these uniforms:
They just look so much faker.