On the OP's car, the inside and outside of the bolsters are vinyl; only the 'seating surfaces', meaning the area in the middle (the perforated one) is leather. It's pretty obvious from the wear the material is vinyl. In fact, only when the material is worn that bad you can tell with 100% accuracy if it's leather or vinyl. The material outside of the bolster is always going to be vinyl, regardless if full leather or not. On full leather vehicles with the regular seats or 14 ways, the inside of the bolsters should be leather, but I'm not sure it is. It'd be obvious the inside and outside materials (with seam in the middle) are different. If they look the same, like on the OP's car, then they're not. Somebody with full leather and 14 ways could tell. Both kinds of sport+ seats are full leather, regardless if interior is full leather or not... and you pay for that with the seat option. Finally, vinyl is supposed to be more durable than leather, but it hasn't been proven. At least on Corvettes, which changed from leather to vinyl on outside bolsters for durability issues since the C5, it's questionable. And seats look like crap IMO. The entire front of the seat (at least) should be leather, but that's the case only with upgraded leather, and not always. The entire seat of leather is very rare, and that's why I really liked the adaptives on 981s, since there's nothing vinyl on them (but you get hard plastic, although looks way better than vinyl sides).