Yes, there's a DL model in the older Aliners. Have the floor inspected carefully on this older model. Older models had known floor issues.
Don't sweat the lack of a water heater-it's an option, even on the new Aliners. Since there's no bathroom, it's no biggie. Our 2012 doesn't have one (we opted not to spend the $400 and have the added weight of one), and we simply bought a cheap hot pot to heat water for dishwashing, etc. It doesn't take up nearly as much room as a hot water heater, and it was about $385 cheaper! It also heats up needed water in about 5-10 minutes.
Older models didn't come with as many amenities as the newer ones. You can have 2 more stabalizers added easily, I'd think. If yours doesn't have brakes, it's not a problem, unless you're towing with a small vehicle. Then it's a problem. We have brakes on our 2012 Classic, but it's nearly 2000 lb. and I tow it with a Pathfinder.
I recommend joining the A Frame group on Facebook - lots of friendly and knowledgeable people there, some of whom own the older Aliners and can answer any questions you might have.