intake question

on the underside of the intake on a 318 2 barrel there is a plate that is factory riveted to the intake (directly under carb) and the rivets have been cut and the plate was welded back on (I believe because the intake was carboned up at some point) there is one spot that the plate isn't totally flush with the intake, will this cause the intake vacuum to draw through this spot and draw oil into the intake runners? I haven't came across this before and have no Idea! is there vacuum under this plate? please help guys