I appreciate everyone for all the very helpful comments.
In my case, the project was bid out and awarded to the lowest bidder. With my department, we are not allow to sole source. The clients we work for understand this as well. They can tell us the type of pipe (copper, steel, plastic, etc.) they want in the project. The purchaser is the contractor, and they are free to use any distributor they want, as long as these products meet technical specifications.
I have project technical specifications. My department uses Arcom MasterSpec. The specification section for natural gas just calls for black steel, ASTM A53, schedule 40, type E or S, grade B; which the pipe distributor claims in the letters that the pipes they are proposing to use will meet. The specification doesn't list approved manufacturers. And it doesn't ask for COC, MTR, or MTC, and does not mention that the pipes have to be manufactured in the USA. It is my job now to determine if this submittal from the contractor meet my specifications. The part that concerns me is the "Global sourced steel pipe, meeting ASTM A53, type E, grade B" in the submittal. I just don't know how I would be able to confirm this.
Is it correct that the MTR can only be provided after I have accepted a pipe distributor and that the pipes have been made and tested? Or are the pipes and MTR already sitting in a warehouse waiting to be used?
I think with the MTR, I can at least look at the chemical composition and tensile strength to ensure they meet grade of pipe...that is if I can trust the MTR.