There always would have been a control capsule and maybe a standby crew. The later system deployments were able to operate more silo clusters from a single control capsule. The conclusive discrimination is whether there is evidence of an elevator for the missile (Titan I) or exhaust ducts to the surface from the silo bottom (Titan II). Wikipedia has fairly good entries on these systems and a listing of the bases and locations where they were deployed, so you could probably correlate your location with that information. Right outside Denver is pretty distinctive.