The ad says it's stainless.
The "150th Anniversary" is Browning's 150th, not the HPs. I have a couple of the hats that Browning put out that have the same "150" logo as the gun.
It's a real edition of the HP put out by Browning, nothing subversive there. The guy who wrote the ad didn't know an awful lot about HPs, but that's par for the course.
Wes