as others have said, the HPMP stands for high pressure/magnetic particle tested.
not all bravo co. uppers have the BFH marking as they sell both hammer forged and non-hammer forged barrels,
so not having that stamping does not necessarily mean that your barrel isnt a bravo company.

My bravo company barrel has these markings right in front of the FSB as others have shown in the pics.

if you have a BCM bolt, these markings (HP/MP only) will be laser engraved into the side if it as well

hope this helps,
Kenny