I'm not sure who might actually make them. I have a WOA carrier with a bolt from Noveske in an AR project and all is good. It's staked properly and I can't complain a bit.
Sorry this doesn't help but maybe the folks at ARFCOM can tell you or maybe ask ADCO. They carry WOA and do well with it.
they do Not make them in house. I believe he uses FN parts. I asked him when I ordered an upper, but he wouldn't say for sure. He said they were from a manufacturer that the US military buys from.
I will say it is hard to get specifics from a lot of AR manufactures and distributors.
As long as every thing is staked correctly and not from DPMS or Model 1...you should be good to go. If you want Tier 1 parts without questions, just go with LMT, Colt, BCM, Young. Sometimes it is easier to just buy those names with piece of mind, then trying to figure out who some manufactures are buying from.