I'm actually pretty surprised this is accurate! Cool find!
In my experience these placards are never really updated. They ones at Dyess had the freq for ground crews listed as an old non-trunked freq.
That being said, aircraft like the B-1 have their freqs programmed into the radio and they pretty much operate like simple channels with the actual frequencies never being displayed. I had to get with an OAS homie to get the freqs for my last base...
Not asking for any self incrimination...but did anyone give you any hassle about snapping a pic?