Well up until a couple of months ago it was technically illegal. But a guy producing and selling Stormtrooper helmets (in the UK) took lucasfilm to court and won the right to sell them as they was considered free of ownership because 25 years had passed since copyright and in the case of "props" and not "art" (or is it the other way round i can't remember now) don't hold their copyright past this length of time. Or something like that.
Tho that ruling was specifically for Stormtrooper helmets/outfits, it would be reasonable to assume, given this, that it must be legal for anybody to reproduce and sell basically anything from the film. As unfair as i personally feel that is, i believe in the uk it's a free-for-all on everything Lucas conceived and created back then.