I think the pontoons are filled with foam (at least according to the Stabicraft website). If they are air chambers, they wouldn't pass upright/level flotation test. The test requires that the two largest air chambers be filled with water during the test, and none of the air chambers can be larger than 0.5ft3. Any ports on the pontoon would likely just be where they filled it with foam, and are left in place for inspection. I know that boats over 20ft don't need to pass, but I think they design all models on the same principal.
I like the idea that the foam is above the waterline, so less likely to get saturated versus the traditional foam below deck. However, I don't see the pontoons as fundamentally safer than below deck foam. If you look on the Stabicraft website, you can see photos of the boat swamped during testing - its really low in the water. A swamped stabicraft is effectively a half submerged life raft, with water up to your thighs. Traditional foam below the floor is going to float you higher up - and if safety is your real concern, its not going to come close to the performance of a boston whaler.
I wouldn't kick one out my garage, but for the money I'd go talk to Jaxon, Bridgeview, Jasper, Walker, etc.