I feel the "SNL" tag is all marketing. The 12 STI tubes, each with the bases, ALL fit into the official gauge. I was asked once by a Range Master/Match director who was running my squad, if my mags were legal. It was mentioned in jest, but I was worried. Next match, with gauge in hand, I went directly to the gentlemen and showed the results.
Once the gauge was seen, mags were appearing out of belts and trunks... Zero failures on SNL pads that DID NOT HAVE the Dawson tape. Several skateboard taped pads had to be squeezed into the gauge. Which I could imaging some persons claiming they were not legal due to not resting on the "gauge pad".