These were available at the 2005 East Penn Trolley Meet, all that I know about them is what is in the photos.
Unfortunately, I did not include the vendor's name in any of the photos. They were taken to show a friend who had five of the NJCB (four MPs and one MPB) cars that more decent-looking MP-54s could be had. I do remember writing down the contact information but that paper was given to my friend. I never gave any serious thought to getting any as I do not like kits. Note that my ideas changed about ten or so years later and I was able to get four MP-54s that were unfortunately done up for Bedford Terminal: note that I have found absolutely no information about the BT.