Dual launch rails on SU24??

While flicking through EnglishRussia there were some pictures taken at a Museum in Moscow (doesnt say which).

On display is a SU24 with a side pylon mounted on the wing pylon.
Cant say I have ever seen this set up before (and often wondered why they didnt have such a set up!)

Is this a real set up or did the museum staff “attach” a fake pylon to the side??