I've become very Snow Leopard-centric and completely forgot Leopard supports PowerPC, too. I was thinking Tiger was the last one to support it. I've always had an Intel Mac Pro, so I've never had to think in terms of PowerPC.
I know that Apple wouldn't know he upgraded his OS through retail, but I was wondering if there was any way to prove it. Probably not. Just wishful thinking for my friend.
I know that "that's just how Apple does things" but it's lame to me that they don't make the final PowerPC OS available for purchase for those who still use (and love) their PowerPC Macs. It's been a few years, yes, but Nintendo made parts available for the NES for 20 years after it was no longer available for purchase. And all I'm talking about is some DVD discs to install it. For purchase.