Lionel DID have it before MTH, and both had appeared at York. I remember when MTH bought it they had a contest for a new track plan design, but never changed it other than to add a few of their own accessories. I have the model (or rather, my daughter does) and I found the red Dodge Ram pickup to go with it. Looks pretty cool when it's all lit up.
At one point Harry sold sets of the trailer, a red pickup, and also a little figure that was supposed to be his dog as a package deal (I recall buying 2 sets). He provided a little paper cut out license plate the buyer could affix to the pickup to match his plates (the plates said Big Mo in some form, but I forget any spacing/punctuation that may have been part of the plate)
IIRC (I don't have pictures since this was both before I had a digicam and also before photos were allowed at York) a few of those accessories may have just had the Lionel markings scraped off and replaced with the letters MTH! (I'm thinking it was either a control tower or radar tower - where LIONEL is on the side of the structure) Obviously as Mike's line of accessories matured, he replaced those with ones already clearly defined as MTH products.
-Dave