Mark is quite right - the only models that will work with the Montgomery county system are as follows - and we have Wiki pages on each of these models, so you can do your research right from here...
Handhelds (RS) PRO-96
(Uniden) BC296D (discontinued), BCD396T
Base/Mobiles (RS) PRO-2096
(Uniden) BCD996, BC796D(discontinued)
The Uniden BC250 and 785 will do digital only with an optional card (BC25i) - which is getting harder and harder to find. These 2 radios will not be supported by Uniden when rebanding finally happens, so I would avoid these 2 radios for hearing 800 Mhz Moto digital systems.
The SC230, BC246, BR330T, and BCD15 will not work with digital systems. Neither will the RS PRO-97 or 2055.
73s Mike