Why should that be part of "the requirements"?
If you buy an HP inkjet printer, you don't really care that it's (for example), actually "HP by Solectron" (the contract manufacturer where I used to work; NYSE symbol SLR) or any of the other contract manufacturers they may have used. HP is the point of contact for marketing, product support, etc., and they never are expected to involve the end users with the details of their outsource arrangements.
Or to take an example closer to home: If you buy an emergency parachute system for a light airplane, all you need to deal with is the end integrator of the parachute system - it's just a "Second Chance" or "Ballistic Recovery Systems" or whoever branded product. You're not engaged with the fact that the little rocket motor (about an "H" or "I" in the sport rocket size scale) which stretches out the parachute on ejection was originally made for them by someone like I.S.P., are you?
Why should this is not be acceptable for rocket motors? Most potential "outsource manufacturers" probably sell in wholesale lots made on order for customers who take care of the details of "product lines" and "marketing" - why should the sport rocketry market _not_ write "the requirements" such that we can take advantage of this manufacturing resource, instead of insisting that the "actual manufacturer" be the one to offer a product line for certification?? (They wouldn't be the ones have "catalogs" or "advertisments" or any of the stuff that TRA policies seem to call for as evidence that motors are "commercial" enough for them; to "the actual manufacturer", it's just one more pallet-load of one more customer part number.)
-dave w