Howdy
Like Hedely sez, there are no official SASS rules for Wild Bunch matches. It is not an officially recognized SASS affiliated activity and SASS has adopted a hands off policy regarding Wild Bunch matches. The rules are up to the local match director, so it's always best to call before you show up, rather than show up with something you may not be able to use.
Most Wild Bunch matches will allow just about any 1911 as long as it doesn't have fancy modern type sights on it. Some might allow simple adjustable sights, some might not. I attend a WIld Bunch match every year in Rhode Island that allows almost anything. I have shown up with lots of my old Double Action pencil barrel revolvers. It's a real treat to get to use these in a match. Last year I brought my brace of S&W Model 1917s in 45ACP. I've shot Colt Police Positives, S&W M&Ps, and I even got to shoot a Triple Lock once. I've seen Lugers, Broomstick Mausers, and stuff I don't even know what it was. I may bring my Browning Pocket Auto for one stage this year. You know, the gun that started World War One.
One guy even had a British Lee Enfield complete with the bayonette one year. We kept hollering for him to charge. The other great thing about these matches is we get to stoke the '97s at the loading table. I forget now if mine will hold 5 or 6, but I fill it up and then let loose.
But it's all up to the local club.