Wow, 1/72 scale? I don't know of any aftermarket interior sets in any scale marketed for the M60 series, let alone 1/72. You'd probably be better off scratch building anyway in that scale, because you won't be able to see much through the hatches. The basics are a gun breech, round inset turret floor with non-skid surface, storage and ammo boxes at the rear of the interior-- radio rack/ammo storage in the bustle, gunner seat on the right, loaders fold up seat on the left, TCs seat hanging from the copula with a step on the turret floor. Drivers position was simple-- tractor type seat with a black or green cushion, removable seat back, instrument panel in front and to the lower right, bicycle type steering mechanism. A Thin sheet of evergreen plastic and some slivers of sprue and you could do it in 1/72nd. You'd need an electron microscope to see much though!
VR, Russ