Model number. I am sure there are better resources, but you can try comparing here:
G5 700/800/VHF or UHF, G4 700/800 MHz only, G3 VHF/UHF, G2 VHF or UHF, and G1 lowband, VHF or UHF emergency alert recievers
www.magnumelectronics.com
G5B64BF-SXUCEN is 400-470
G5B64BF-SXUDEN is 450-520
If I had to guess G5B64BF-SXUBEN is probably going to be the federal range (380MHz)