I have experience with these models. You can for sure do narrowband without any firmware upgrades. If you want MDC-1200 signalling, however, you would need to upgrade the firmware (provided it isn't already upgraded, that is).
Scanning Philly, Bucks, Eastern MontCo, & DelCo Fire.
Base radios: TK-7180 VHF, TK-8180 UHF, CDM-750 VHF, Pro-197, PSR-800
Mobile radios: NX-700 VHF, NX-800 UHF, Pro-96, & Wouxun HT.