Every Backwoods or Avalanche I’ve had has always been stamped with alloy grade. If it was stamped 6061 then you would know for sure but it seems they never are stamped when folk are claiming to be something better.
Lots , and I mean lots of people buy stickers to make their bikes look or appear better than they are. The amount of mis stickered bikes I buy is uncanny.
I bought a “Zaskar” last year which the person was adamant they purchased new. It was a Avalanche in a frock.
I don’t doubt that manufacturers upgrade items when they run out of material. It’s cheaper than stopping production. Ford up-spec cars all the time in various ways if they run out of a item but it doesn’t mean the car is has gone up a level.