i presume you mean pieces or chunks of caramel? this is ill-advised, as it will make chewing the brownies a less enjoyable experience. and by the next day, the caramel will be harder than the rest of the brownies.
you are also mistaken that fudge brownies contain fudge. the "fudge" is used as an adjective here, and refers to the "fudgy" texture, as opposed to cake brownies, which have a texture closer to cake.
for your case, i would buy some more syrupy caramel ice cream topping (not the thicker caramel, but the kind in a squeeze bottle), or a caramel flavoring. mix it in the batter, so it is like a swirl in it. not only will it look good, but the consistency will be better, and it should still cook close to as well. just don't use too much caramel, as the flavor should be meant as a complement to the cocoa, not on equal grounds.