Is Gretsch-Unitas fanlight hardware the best? Looking at a house for sale that has GU stamped on the...

Looking at a house for sale that has GU stamped on the inside of thier window. The windows are incredible as the fully open resembling a door and then when the handle is up the top tilts forward. The simply markings I find is GU on the hardware that surrounds the inside of the window. I'm trying to find the manufacture of the glass (if it is different from Gretsch-Unitas). Thank you!