My 2.7L replacement water pump, which is a Zim's rebuilt unit, has two protruding inserts or collars in two pf the bolt holes (circled). The protruding inserts/collars don't allow the pump to bolt flush to the block -- the bolt holes they line up with on the block aren't big enough to take them. The water pump I just removed doesn't have these.
What's going on? Are some blocks drilled to take these, and others aren't? Do new pumps have these, or are these only found on some rebuilds?
And if your block isn't drilled for these, are you supposed to remove them?
Side view to show how far they protrude:
