Guys, Thanks for all the help. I think we are getting to the bottom of this.
Clem, Yes, this a dummy (Non Powered, or NP) unit. You are quite correct in that the mentioned wheel set is not seated correctly. That is part of the problem. It will not seat correctly in any of the 6 slots available. The flat tipped pins make no difference in the way the wheel set goes in. I left them installed.
Clem and WillyGee, I did try your suggestion to install the truck plates without the wheel sets. The rear truck is perfect. 
This is how it should look. And all 4 screws bottom out very nicely.
Here is the front truck, up close and personal. We have issues. The yellow arrow shows a larger gap than is present in the same position on the rear truck. So the plate is likely warped from the wheel set not seating correctly. The red arrow shows a screw that does not bottom out. Notice the head is elevated and threads are showing. I have it as tight in the hole as I dare.
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I returned to the back truck, since it has fewer issues. I installed both blind wheel sets (they went right in), and the tried each of the remaining flanged sets. 2 seated correctly and 2 did not. I put the truck together with the good flanged sets and on blind set. So now the rear truck is problem free.
The front truck now has the following issues: a) a screw that does not go in all the way, b) a warped plastic wheel set plate, and c) 2 flanged wheel sets that do not seat properly.
Time to call MTH for parts.
Chris
LVHR
