Centralize the completion of these requests. The Corp Secretary or other officer will have the seal, so all of these types of requests go through that office. As far as medalion and signature guarantee stamps, as long as you have trained the people using them you could produce them for every person at the bank if you wanted to (don't know why you would, but you could). Similarly, there is no law I am aware of that says you can only have one corporate seal, but you sure don't want them floating around all over the place.
But, the main issue for me is why the individual branches are completing this process. Centralized admin for opening accounts at Treasury, or any process that requires a corporate guarantee, seems prudent.