Most years have the solar prewire, my 2011 did. The key things that vary overtime are color of interior (cabinets, rear wall, etc), flooring, cushion covers (mine are cloth, new is ultra leather), and perhaps some lighting. You can replace all halogen bulbs with LED through the entire trailer for $25, so I wouldn’t let that away your decision.
Some newer models may have a quieter furnace, not sure what year they switched.
“Older” models like my ‘11 have MicroPulse tank sensors.
At some point they made the radio more fancy and may connect to the TV, if that matters to you. I wouldn’t worry about antenna differences, that is $100 and 15 minutes to swap to any of the options that exist.
I do wish mine had the window in the door, but not enough to pay the higher price of new