Yes, this is HPT tested/MPI marked.
Mr. AERO PRECISION USA- The answer is NO!!!! (I asked: is it stamped in the bolt MPI/HPT?).
It is NOT marked or stamped HPT.
I order it and the quality is bad. The pins are push to one side and sticking out. The one I received the gas key and bolt channel are NOT Chrome lined. I believe they use the same manufacturer as the cheaper brands. I love aero lowers but that’s it. I have detailed photos that I am happy to share.