That is an 06' to 09' model year you have pictured. The apex of the fender well is round on these and the headlights have a little nook in the bottom.
03' to 05' models have a squared off fender well and no nook in the headlights.

None of the 4th gens came with a manual shift transfer case, so you have to make sure the electronic servo engages the 4x4 properly. The electronics can get corroded. The servo motor and gears can become sticky or seize up completely. Mostly from lack of use. Replacing this part or the T-case is expensive. You can swap in a manual T-case if you want that option. It's not the easiest job I've ever done, but it's doable for us weekend wrenchers.
There are also some 2wd versions out there, but imo only practical for grocery getting, soccer moms or towing.

If you find a 4th gen with a 4.7 V8 that's in decent shape, buy it. The 2UZ FE engine code is arguably one of the best and most reliable engines ever built. There are 2 early Tundras with this engine that have documented 1 million miles on them. They were a couple of trucks that Toyota actually bought back from the company that owned them.

Also note that Toyota built the V8 06' -09' models with more power and torque than the 03' -05' models. Also the 4x4 V8s and the V6 Limiteds came w AWD, locking center diff and of course 4Lo. The AWD feature works really well for Wet and icy roads.

All of the Lexus sister GX470s came with the 4.7 V8, so if you find one you can afford, buy it.
The 4Runners 4.0 V6 gas mileage compared to the V8 is not that great, so for me the V8 is the better buy.

Good Luck!