Yes, the MY16 models have DPF but prior to that don't.
The MY16 models got a new front end (grill, lights, bonnet etc), new dash layout, new media unit/centre column with softer touch materials on sides of centre dash column where you naturally rest your legs, new tail lights, and I'm pretty sure they got new injectors to go with the DPF and power increase from 195kw to 200kw (torque stayed the same).
I also believe there were some remapping of the transmission as well. I have the MY16 model and have never driven an older version to compare but from what others have said on various forums the MY16 transmission locks the torque converter in 6th far quicker. Also the PWR button (essentially sharpening up the throttle) makes a big difference in the MY16's where as others have said it didn't really do much on previous models. VX & Sahara also went to 18" wheels in MY16, with bigger front brakes so 17" wheels won't fit, not even Toyota rims (I believe ROH do make a 17" rim that fits but that is the only one as far as I'm aware).
I think from late on in 2016 they also dropped to a single starter battery. Mine's a mid-16 build and still has 2 starter batteries but I'm sure they changed that later in the year.
For me, the only reason to go pre-16 would be if you were wanting to do a lot of big power upgrades and wanted to change the exhaust. There are some DPF back exhaust upgrades but I'm guessing they don't give the performance upgrades that a non-DPF exhaust would. I guess if you do a lot of stop/start city driving you would also be better with a pre-16 so there's no risk of clogging the DPF. Otherwise I'd say get the MY16. It's much nicer inside (in my opinion) and looks a lot more modern. I've do plenty of 1hr or more trips and I've never even noticed the DPF regen cycle on mine so the DPF is a non-issue for me. The MY16 goes better, stops better, and has a better programmed transmission (although the transmission is still a bit of a let down to be honest).
If you're specifically looking at GXL I think they changed whether or not there were any steering wheel controls a few times over the years so if that's something you want then you'd need to check whether the specific car you're looking at has them. I know the MY16 GXL's didn't, but I think the MY15 and MY17 did. Go figure!