I worked at a Shakeys in CA from 1980 to 1995. The original sauce recipe was made up from scratch, using canned tomato puree as the base. It was very spicy and distinct. In the early 80's, as the company began to expand, more of the products had to be purchased from distributors. Dough came in mixes, and sauce came in a bag in a box.
Ours was one of the original Shakey's, and we hung on until forced to move from the original recipes to the packaged product.. It was especially noticeable in the sauce, with the new sauce being quite bland.
It's been over twenty years, but I think that I have the original sauce and thin dough recipes. These would be the original full size recipes, and would have to be scaled down. But I was looking to see if the sauce recipe was online before comitting to the search.