The latest Pizza Hut ingredients list that I am aware of is the one at http://www.pizzahut.com/Files/PDF/PIZZA%20HUT%20INGREDIENT%20STATEMENTS%202008.pdf.
As you can see, for the Regular Pizza Sauce, the ingredients are given as:
Tomato paste, water, salt, spices, garlic powder, and citric acid
That same description goes back to at least 2006. Trying to reproduce that sauce to get what PH may be using in its stores would require insider information to get a clone quickly. Otherwise, you would have to conduct taste tests, most likely quite a few of them, to get something close. Even then, your clone could be different from someone else's, because of differences in taste sensitivities, etc.
The above aside, I think your sauce recipe is as good as any to try at this point. However, you might want to double check the tomato paste you plan to use to be sure that it includes salt. My recollection is that not all tomato pastes include salt. Also, PH does not use MSG. That is an ingredient that FDA regulations would require be disclosed because of allergic and other sensitivities to MSG. However, it is your sauce and if you want to use it, that is your call. You should also decide whether to include sugar, which is not in the Regular Pizza Sauce ingredients list given above. I might add that there is a PH Sweet Pizza Sauce with the following ingredients:
Tomato paste, water, high fructose corn syrup, salt, dry garlic, spices, and citric acid
The main difference between the two sauces seems to be the high fructose corn syrup that is used in the Sweet Pizza Sauce. Unless you have a source of high fructose corn syrup (which I understand is not the same as regular corn syrup), I would use ordinary table sugar.
Please let us know how your sauce turns out and if it is anything like a PH pizza sauce.
EDIT (4/20/13): For the Wayback Machine link to the above Pizza Hut pdf document, see http://web.archive.org/web/20100602083641/http://www.pizzahut.com/Files/PDF/PIZZA%20HUT%20INGREDIENT%20STATEMENTS%20September%202008.pdf