From a letter sent to me by D.E. Watters
I came across some interesting SPAS information today. I went to the local university library and found their collection of "Jane's Infantry Weapons" annual. From the 1983-84 to 1988-89 annuals, the books contained a section on shotguns. Evidently, Franchi introduced its first SPAS shotgun in October 1979 and there was at least one SPAS model before the SPAS12.
The earlier editions include photos of the SPAS11 (!) and the 1983-84 edition even has a photo of a SPAS12 with a SPAS15-style grip safety. The section on the SPAS15 mentions that the SPAS14 was a SPAS12 fitted with a box magazine, and that the first SPAS15 prototypes were completed in 1984. The 1986-87 edition even has a photo of a cute select fire bullpup in .410 that Franchi had been playing with. It had a 15rd box magazine and fired 200rpm on full-auto. (Chris's note: My kind of gun!)
By the way, have you ever come across any mention of a full-auto SPAS12? Personally I haven't, but I have a friend who swears that he has seen references to one. Perhaps he is confusing the SPAS12 with the USAS12, which was available in a selective fire version. (Chris's note: Anyone out there have any information about this?)