A pic would help.
From your description it sounds like a rib cut off of the backbone. You'd have a decent piece of meat running down one side of the long bone - the sirloin. The other side of the long bone would have a small piece of meat - the tenderloin. They sound like good ones.
Yes, similar to a T-Bone or Porterhouse steak but of course smaller.
If you like the taste of lamb, treat them gently. A simple S&P rub would probably do it - go light on the salt. If you have to use oak, I'd probably go for 40 minutes; 60 minutes on a lighter wood.
The chops are pretty much raw at this point. Press one or two with your finger. It should feel pretty soft.
Then, onto the grill. Maybe a light rub of OO and oil the grill grate. I like mine medium-rare but to each their own. Use your grill on medium if you can.
Start with two minutes per side. After four minutes, press the chop with your finger again. If it feels really soft, it's rare. If it feels firmer you're pushing medium rare to medium. If it feels really firm, well you've overcooked 'em. The finger test works well on anything thin you're doing on the grill. It takes a little practice.
Good luck to you.