I think it depends on the year, but for the overlap I would say no.
As far as the 340 manifolds go, there are three different sets: 1968-71, which are the ones everyone pictures in their minds; 1972, which use the same LH manifold but lost the header-style RH piece, and 1973 which is just a pair of 360 manifolds (LH is the same as '72).