I have a Sunn PA, complete with cabinets. Not the Beach Boys Coliseum PA, a smaller one. The cabinets are 24" wide, 30" or 36" high (I'm at work, and can't go measure them). They contain one D130 and a right-angle horn with the LE-100S driver, only one of which works. There is no separate enclosure. As you said, Joe, there's no need, as the LE-100S/horm assembly is completely enclosed. No inside baffles.
I'm not sure about the sensitivity ratings for the D series, but the K series is said to be almost identical. Sensitivity for the K130 is 103dB/1w/1m, swept from 500-2500Hz. For the K140, it's 98dB.
The thing to remember about sensitivity ratings is that there is no standard for measurement. JBL is usually pretty conservative with their ratings, so much so that they felt it necessary to explain their methods and why their ratings might be lower than those of other companies. Some companies measure at 1000Hz only. Others might run a full frequency test, then publish the highest number achieved. In that way, a driver might have a 100dB rating, but if that is achieved only in the breakup region at 4KHz, that doesn't make it a very useful rating for a bass driver!