Not a problem. Due to the design, almost all the older style Colt DAs do not fully lock if the hammer is cocked slowly or the cylinder is held back. The reason is that the Colt double pawl hand cannot force the cylinder into full lockup and still have room for trigger motion to fire the gun. In other words, your guns are normal.
I would like to add a couple of points on checking out a revolver. Along the lines of the above, a Colt with a worn cylinder stop can actually be forced out of alignment by the hand. This is a point to check on a used gun.
Also, look at the screws. Ideally, they should be untouched, meaning that the gun has not been messed with. If the screw heads are battered and worn, it means the sideplate has been off, probably many times. A gun like that may have a smooth trigger, but the parts may have been polished out of time or (if a S&W) the case hardening cut through so the parts will wear out rapidly. Many guns subjected to amateur gunsmithing turn up on the used gun market when the guy realizes he has messed up.