Thxs for your thoughts KD. I agree that the most likely scenario for the date codes is that the month-year was reversed.
I hadn't considered the possibility that all the USA Super Prestige or even all the USA Tommasini for 1991 may have had the special shell and only the special edition versions would have the unique paint and brass head badge. Still, Roman's and some of the other 15th anniversary paint schemes I've seen aren't in the 1990 & 1991 Colorado Cyclist catalogues. This begs the questions of whether these BB shells were used for in all markets for 1991 and not just the USA. It might explain how a supposed USA model found it's way to him.
BTW, I've checked my 1990-1991 magazines and Wm. Lewis had cut his advertising budget and was running smaller, classified type advertisements. The Tommasini advertisement was B&W, showing the front half of a frame. During this era, he seemed more interested in promoting Quattro Assi and Roval wheels.
FYI, I also had a quick look back through my late 1970s issues of Bicycling. Fortunately, the advertisers are indexed which made it easy to look for Wm. Lewis. Unfortunately, he wasn't advertising with them at time, so even if he was the Tommasini importer during this era, I have no evidence of it.