Gomer and Sgt Carter shopping for an engagement ring...
Last time I came upon an ep of GPUSMC, the set-up was the Carter wanted Gomer to ask Luann to marry him so that Gomer wouldn't re-up when his tour was over, thus finally getting Gomer out of his hair.
Gomer and Carter end up at a jewelry store, with Carter being all nicey-nicey and pushing Gomer to get a ring. A clerk is watching and interacting with them and he gets this great shocked/amused expression that tells the audience that he thinks that Gomer will give the ring to Carter, not Luann.
It amazed me to see this episode now, knowing that if the network censors had been on the ball, this scene would not have been shown. I imagine a lot of the GPUSMC was oblivious and just thought it was silly for two men to get married, and didn't know about gay dudes. Also imagine a lot of viewers got the joke, but weren't going to try to explain it to Aunt Bertha.