My '89 Chevy 1/2 ton was set-up with plugs. That's why I mentioned it. HOPEFULLY... BTD's truck has had an alignment before now; but I thought I would bring it up.
The reason GM set them up like this was to make for a quicker, more consistant build on the assembly line. The "net hole" which was formed with the plugs in place was a no-brainer for the guy sticking the bolt through the hole and, not having to set the alignment on every truck, saved a lot of time, money and tooling.
Mark