I'm happy to report that my fears were unfounded and my wife and I enjoyed the lamb.
I had the option between sirloin chops and loin chops and since this was an exploratory mission I went with the sirloin chops...because they were cheaper.
As mentioned, one chop received salt and pepper and the other salt and the Planet Barbecue rub.
The chops rested in the fridge for about 5 hours before I put them over direct heat.
They cooked for about 6 minutes per side with the lid closed and the heat was around medium to medium-high.
Overall the chops were pretty close to medium; they look more like medium-rare here but some of that's tinting from the juices.
Since lamb is popular in the Middle East I cooked up some couscous to serve on the side - no credit taken; it was a box mix.
We both felt the chops had a strong resemblance to steak but with a slightly sweeter flavor, and we liked them. I'll definitely cook lamb again (and not quite as done) and it'll be from Pinn-Oak. I'm happy everything worked out but I'm still not confident enough to buy random store lamb.