Ray, thats true. In most of the applications we would use it for, its probably fine. There is (fortunately and unfortunately) alot of leeway for the experimental industry, especially in the US. Alot of 'race car parts' on these planes.
Kinda like AN adapters----some are marked and are the real thing, with the 'real' pricing, some are not. Now for full disclosure----we DO make some of ours, and no they are NOT stamped. They have been manufactured to the mil spec drawings, even class 3 threads, but since we dont have a TSO, or a PMA from the FAA ( and not because we havent tried to do so, but waiting 4 years is kinda ridiculous. Thanks COVID. ) we cant stamp them legally. In the certified world they arent accepted without documentation, but for experimentals, its a different story.
So when we set out to begin manufacturing some of our own, Steve and I took the Mil Spec drawings and criteria and made the adapters conform to that.
Tom