I don't think that the prop-makers did any modification of a welder's gauntlet to make Luke's gauntlet, other than to add the comm pad. Maybe the comm pad covers a logo.
I have not researched Han's glove, though, so I can not tell whether they are exactly the same. But I do know that the Hoth Trench Soldier's gauntlets are different.
The glove on Luke's gauntlet should be of white leather with seams on the inside.
The cuff should be of light grey suade. The cuff should be in two pieces with seams on the left and right side.
I got some cheap welder's gauntlet. I modified the cuff somewhat, removing the logo on the right gauntlet (replacing with material from yet another gauntlet) and making a second cuff seam. Not too accurate angles of the cuff seam, or length, but I think good enough for costuming.
http://i22.photobucket.com/albums/b345/DarthLars/Pilot/jackettest.jpg
http://i22.photobucket.com/albums/b345/DarthLars/Pilot/Hothcommpad02.jpg
Original gauntlet closeup seen below:
http://i22.photobucket.com/albums/b345/DarthLars/Pilot/Commpaddetail.jpg