Current model HT PJ's -merely software upgrades?

I recently spoke with JVC Pro division - for their consumer home video projectors -and, it appears that the real only changes over the last several years of models ARE SOFTWARE UPGRADES!!! RRREEEEAAAAAAAALLLLY?!
I happened to call jvc after purchasing what I believed to be an RS56 THX projector, because I was concerned that perhaps the stickers (yes, that's about all that differentiates some of these models, cosmetically, it seams) that included the serial number and model numbers, were likely tampered with or had been replaced! Turns out from discussing, that the only way to tell some of these models apart (like RS56 from RS66, and RS 56 from RS55 or 50, IS TO GO INTO THE MENUS AND LOOK FOR DIFFERENCES!!! WOW! I AM SHOCKED! They informed me that not even opening the top lids, and looking for markings or differences in the guts themselves, would differentiate what's what?!
You mean to tell me that JVC has only been updating software over the last 3 years, and simply doing reprinted boxes and service manuals!?!! Im aghast! Well..almost. I have seen the latest RS56u, and it's STELLAR looking, true. So, I know that you are at least getting a quality piece. Im just not so sure what more value Im getting vs older X7,RS-40, 45, 50, etc
Anyone else here have any experience, knowledge, or a take on any of this? I mean I knew the products have not looked any different (like old Epson PJ's) over the last few, but I at least figured some upgraded electronics and internal parts, er something. NO DICE, is what I gathered from conversing with JVC Tech's for 45 minutes, of and on.
I just expected quite a bit more for thousands of dollars difference on the used market, model to model.