i have seen some of those plates with, and some without. however, my experience has been with early 318's and 360's. who knows what went on with those engines before i got them.
as a side note, i always drill extra holes between the ones drilled in the original plate if i have the plate off.
i read that in a direct connection manual one time, and i figure it can't hurt.
make sure you deburr the extra holes thoroughly, so no metal gets a chance to be ingested.