The plugs are simply ultra-lightweight wood that's been glued in Tom so the bats are fine re type A. I spoke to the guys at M&H about this, it's basically a gimmick to lighten the bat a bit without altering the pickup. Not sure how much of a difference it makes though.
As the blade must be made solely from wood, glueing in the plugs makes the bat illegal according to law six. If, however, you were to make oversized plugs, hammer them in and then sand them down to the level of the bat surface, you would comply with law six.... However, after much use the plugs may come out!
I don't know whether they are glued in but I would suspect it would be difficult to sell the bat without that, so I suspect that it is not strictly a type A bat, or even type B or C under the rules.
My interpretation of the bat description was that it gave you a bat similar to the solution but with a significantly lighter pick-up.