Yes, I remember once. It did the 179/242 x-over somemore!
But it has also appeared another one or two times as a fully 242
bus (as in not an x-over from 179).
179 has been the favourite dumping ground for SLBP... 
In the past, when there were less SP ADDs, they took
the 179 ADDS to cameo on the long distance svcs (30, 154, 174),
then placed all the NAC MK2s on 179...
All types of SLBP buses have cameod on 179 before (except CNG,
B9TL). Even 1881T & 1888A has cameod before too!
