I have worked for a number of tech hardware companies over the years, and in the manufacturing line areas there was always a test-jig or other 'custom made testing tool' which was based on a gutted model of our earlier products. It was always easier to grab an old hardware unit and Frankenstein whatever we needed to have access to for new models testing. (power supplies, I/O components, displays and processors, etc). They may in fact be using the entire backbox with a completely different playfield, since they are basically the same across the titles. It is quite possible that if they zoomed in on the Hobbit machine, you might be horrified at what they have done to it! 8-)

But then again, it may just be an old machine where the assembly line folks can simply take a break and unwind for 15 minutes...