Inner sactum oil galley plug

I was thinking that with no plug there would be no "pressure drop" from the flow restriction of the filter (as noted it would shoot straight up to the gauge) & it will be slightly higher . it might only be a small psi difference but by the nature of the beast it has to be something for it (a filter) to function. Yes I've seen it in Ma's literature that leaveing it out will cause a pressure reduction & I did think Ma was referring to that specific plug but I think that is a typo & that if the other/seperate rear gallery 3/8 NPT pipe plug on the inside by the intergear is left out you WILL have a pressure problem.