I think you might be mistaking lamb breast ribs with rack of lamb. Rack of lamb benefits from a hot and fast cook and 130 is the appropriate internal temp as you state.
Lamb breast ribs filled with connective tissue and fat and are generally braised for an hour and then roasted or grilled.
I suspect that one could do a 3.2.1 variation and do pretty well. Not sure as to the braising liquid though. I'll let others comment there.
However, based on my own experience with pork spare ribs, I'd recommend trimming as much fat as possible, seasoning with salt and pepper, and then smoking them a little bit hotter than normal, around 275, for about three hours. Use the standard doneness tests (poke the meet with a toothpick to test resistance and see how flexible the rack is when lifted by tongs in the middle.) and finish with mint sauce (generally vinegar, some kind of booze like bourbon and fresh mint).