Crusty fouled EGR hole in intake manifold

[LTBeck41]

I changed the EGR unit a while back and found the port leading into the intake manifold full of something like black grease/goo. Still got EGR codes.

Today I removed the throttle and saw that the first hole you come to in the intake was crusted over with VERY hard crusty black cinder like stuff. I have managed to chip out about a half inch of it. Then I noticed an allen wrench type plug directly below the hole.

Could this be used as a clean out if the allen plug is removed? How much tapping/hammering could this area withstand?

How far and straight is this hole?

Or should I just take the whole intake manifold from the 2.9 engine on my neighbor's dead BII next door?