I wonder if that dialog balloon is one of the reasons the issue is so scarce. Even in the innocent 1950s, that one would have been noticed!
I could be wrong, but I don't think that meaning/usage of that word existed back then. I think that meaning of that word came into usage quite a bit later than the 1950s. Any one else think so as well, or think otherwise?
I'm with you that most of the double entendre meanings we see in covers and dialog are modern readings that weren't intended by the artists and writers. For instance, until comparatively recently "boner" was a common slang term for a mistake. "Making love" was not (or, at any rate, not only) a euphemism for having sex.
Similarly, the Rifleman 10 cover surely wasn't intended to have the meaning we see in it.
I was thinking, though, that the dialog on the TAR 9 cover might have been meant as a sly wink to knowing (teenage) readers. That reading does depend on when d*i*c*k became a slang term for p*e*n*i*s. Somehow I thought that meaning went back to Shakespeare's day, but maybe not.
I was recently told by some one that he took his copy of Rifleman #10 to an autograph show to be signed by the kid (Johnny Crawford?) and he wouldn't sign it. He was embarrased because apparantly this was a deliberate pose set up by the adults and as a child Johnny? wasn't aware of it.