I just did this last month with my new engine from Vans (drop shipped from Lycoming). I called Vans to see if I really needed to removed the front plug, pierce the inner one and replace the front plug with a new one since the governor drive pad cover and plumbing were in place. The folks at Vans said I would need to remove the front plug, pierce or remove the inner plug and replace the front plug with a new one.
I called Lycoming and after they looked up my engine info, they told me the same thing that Vans said.
I had been told by a few folks that I believe know what they are talking about that it would be okay if I just left all as it was, but I chose to do what Vans and Lycoming said I needed to do.
So, I pierced the front plug with a screwdriver and popped it out. I decided to remove the inner plug altogether since it is just baggage at this point. I pierced the inner plug and could not get it to budge, so a fellow builder lent me his slide hammer with a big screw mounted on the end. I threaded that into one of the holes I had pierced in the inner plug and with a few minor taps with the slider hammer, the plug came loose easily. It took some finagling to get the plug out past the cross tube.
To install the new front plug, I went with Lycoming's suggestion to use a ball peen hammer as the install interface (they also will rent you a proper tool). I set the plug into the crank. It is shaped like a giant steel contact lens. The convex profile to the forward. A few taps with an 8# hammer, the plug dimpled and set in. We shall see if it leaks pretty soon! I hope to have first engine start within an week or two. Made me really nervous to be operating on a brand new engine! I would be less comfortable if I ignored both Vans' and Lycoming's advice though.
I suggest calling them both to see what they say. After bargaining with them, I could not get them to budge on their stances.