I may be wrong but looking at the cam specifications for the 1275/1300 motors they all seem to be the same. Several part numbers, prob for different engines, but the actual cam specs seem to be the same.
Remember new cam = new lifters.
Regarding the oil gallery plugs; this is a probably not a necessity but could not hurt. If you are going to take the motor completely down to the bare block it is probably worth cleaning out the gallery.
I usually pull the plug and then tap the opening for a plug before sending block out for tanking.