Lamb is one of the dishes that is actually easier to do well as a home cook than in a restaurant. It should be about medium rare to just under medium. The problem with lamb is it is touchy. Leave it a bit too long, it goes into well done, and sucks. It is a very tricky meat to get the temperature right. Now if you are just serving it off the grill, it isn't that hard to do, in a restaurant environment, there are a lot of things that can go wrong between plating it and serving it. sits under the salamander for a bit too long? Suddenly the beautiful chop at the exact temperature becomes shoe leather.
Lamb is actually easy to prepare, you can do tricks with sauces and that is another discussion, but in a restaurant getting a decent lamb chop is more a testament to the establishment's organization and communication than the skill of the chef. With a little salt and pepper you can grill a perfect medium rare lamb chop on any fairly hot surface, given a modicum of practice. Now you probably couldn't do one in the middle of a 100 seat meal service, and have it be perfect when it gets to the table, but that is the advantage the home cook has over the pro chef.
I always worry when I see a lamb chop on a menu with a complicated heavy sauce. Heavy sauces cover many sins, and that tells me you aren't sure you'll get it out at the right temperature. Ketchup? Definite red flag there.
TBS