Okay, now that I'm thinking about this, I'm flashing on more details. A couple of tidbits came back to me about the CM in the sentry guard outfit. I remember him telling us how restrictive the costume was and demonstrating by trying to flex his knees. They didn't bend much. Second, I remember looking closely at the "holster," which was really just a sort of flat, right-angled hook to rest those double-barreled guns on. (To my memory, he didn't have the guns on him. I'm not sure if the CMs were ever given those, but I don't recall ever seeing one up close, so I doubt it.)
Note to RegionsBeyond: As noted above, I can corroborate the sentries and humanoids wandering around the park. As for them just being in Tomorrowland, I honestly don't remember. That's certainly reasonable.
indydisneyfan: Did the display you're talking about have the full-size figures of the robots? If so, we must be remembering the same thing.
I wonder what happened to the full-size figures. I've seen photos of miniatures at Comicon a few years ago, but I can't find anything about the full size versions.