Looking at that holster, kind of noticed a couple of things might help identify it.
First, the paddle back on the holster is leather(you can see the stitching in the first two photos). Most of the modern makers are using a plastic paddle.
Second, the edge of the holster in the last picture is pretty thick, probably about 4-5 thicknesses of leather(the holster itself is two front and back, then 2-3 thicknesses in the middle).
I dont know, this looks like either an older model of the Bianchi with a leather paddle, a leather paddle added or it might be a custom job.
I'd say do a search and look for "holster Glock 17 with leather paddle back". Probably be easiest.
BTW When did the switch holsters (season and episode)?