Many TT's have a little AM/FM radio antenna. If there's such a radio inside, and no other antenna outside, then that's what it "was." That ring of sealant formed a great funnel to send rainwater inside.
If there's no music radio, or there IS one and it still works, see if you can put the cable down the hole connector first, leaving a little loop you can grab to pull back out if you ever need to. Then try to pull the sealant off, and put a patch with sealant over the hole. Dicor will come off if you ever have to get back in there.
I'm skeptical about CB because:
1. Much more likely to be used if it's usable on the road and in a TT it isn't.
2. The Connector doesn't look to me, like the PL259 type used for CB
since it doesn't have the prominent center pin as shown on the left side of the pic. There are versions that can be crimped not soldered, with the cable end looking like the crimps in the OP. But the center pin would still be there, and I don't see it.
3. The little bit of the wire I can see, looks to be "two wire" and not Coaxial like CB.
That said, and probably needless to say... Anybody can Wire Any Thing Any Way. AM/FM will play pretty well with almost anything from a coat hanger on up. CB will also listen. Good Transmit takes a LOT of quality work and that's hard to achieve on an RV body.