here in South Dakota we have "reserves" they are volunteer but have power of arrest without going to certification. instead they are certified by the county on their own expense on OC, Baton, Pistol, and whatever else they carry.
If your going to the academy ours is 12 weeks im sure it vary's state to state.
if you take a poly...TELL THE TRUTH! Most agencies dont give a damn if you smoke pit in the past, as long as your truthful and thats what they want.
exam by the board might be a video test on how you would react to certin situations "if you where a LEO" basically they test positioning and personal comunication skills.
about your gun.......EVERYONE wants a gun...our state you must be 21 (thats the min age for a LEO)
this should give you an UP on the class... if this is what will happen!
let us know, and good luck!