LEM expert, Frank O'Brien, tells me that the piece at Franklin Institute is
probably a training article. The reason is that it lacks the in depth plumbing
that is apparent on other units. For awhile, the piece stood out in the open of
Philidelphia, and was heavily vandalized. It was eventually moved to it's
present location. Chicago's LEM is a mockup as well.
For those familiar with the movie "Fly Away Home", about the girl and the gesse,
you might be interested to know that the father in the film is a real person.
He's an artist in Canada, and built his own LEM from sheet metal simply because
he liked the geometry. It was later sold to finance his interest in ultralight
aircraft. I'm told the buyers were from Japan.