Carriers depict the signal icon differently. Sprint and T-Mobile tend to use the "4G" for LTE only. Verizon and AT&T will indicate either "LTE" or "4G LTE" depending on your device.
I talk to corporate like a BAWSS!
DEVICE ► Nexus 5 / Nexus 7
ROM ► Cataclysm / DU
KERNEL ► Trinity / Faux