I have a WE 5302 with GF handset that came from a Independent Telephone Co. that I didn't initially regognize..
I have attached some photos below..
I apologize for the photo quality, I am not terribly good with using my phone's camera..
I have a couple more photos I can post by request as well.
The GF handset was an option for the 5302. As you see it has the same shape and size as the G1 handset on the 500 sets, but accepts the old-style transmitter and receiver elements of the 302 sets, which are optimized to be used with the old 101A induction coil in this telephone. So, electrically this set is still identical to the 302, but has the new styling of the 500 sets. In addition, the GF handset had higher efficiency from its geometry, the transmitter being closer to the speakers mouth. This provided about 5 dB improvement, ca. half of the overall gain of the G1 handset.
The 5302 and companions were available with four different handsets. Initially the traditional F1, and F4 (with 500-style elements), a normal G1, and the GF, added last to the options. Which one was used depended on the local transmission zoning and customer style preference.