Narrowbanding doesn't apply to VHF low, but it is required for VHF high, which is what is listed in the DB for Mono County. However, narrowbanding won't prevent reception. I have no problem listening to narrowbanded channels (in another county), even on my old crystal scanners. The volume is lower, but that's about it. Reception is the same otherwise.
The OP actually mentioned "rebanding", which applies to public safety 800 MHz trunked systems. But unless some agency in Mono County installed one of those since the last DB update, then rebanding wouldn't apply, either.
I think we're going to need to hear from someone in Mono County to know what's currently in use there.