On the GOUT, yes, due to desaturation, but not on older transfers. On the Technidisc LD and on Moth3r's widescreen telecine bootleg, it's blue. From what I've been able to gather, there was much less visible color variance in Luke's saber in theatrical prints from shot to shot than there was in any of the pre-SE video releases. (When the SE came along, it got really messed up.)

Besides, Harmy fixed all of the other shots to be blue, even ones that sometimes turned up looking greenish or white in older transfers.

It's just that it's the one shot in the DE that doesn't match.