Long guns,

Bolt Action (1917 or Springfields) from the WW1 and post-WW1 period, Red Scare, etc., WW2 Civil Defense.
M-1 carbines (back in the 60s during the riots, unknown if issued or taken from Gov't stocks).

Unknown bolt action rifle in .308 for SWAT.
200 surplus USAF M16s (converted to semi-auto only) in locked metal containers somewhere.