I learned long ago to never get my hopes up at MA gun shows. Don't expect to find deals, don't expect to find what you're looking for, in fact, don't expect anything except for a little entertainment. For every "deal" there is out there, there are a dozen tables full of run-of-the-mill guns that vendors have marked up specifically for the show.
I think the internet era has killed the traditional gun show - if there's something specific you're looking for, no matter how common or rare, you can probably find it easier and for less from the comfort of your own couch.
Gun shows are for finding things you didn't know you needed and don't mind paying for.