Some people just plain want bigger dogs, and many CLAIM their dog is 120 lbs but not. But yes, there ARE Shiloh and King Shepherds that were specifically bred to be oversized, tend to be long-haired, and are often claimed to be mixed with Malamute to help the size. They certainly tend to be square built and straight legged like Mals.
A good German Shepherd should be anywhere from 60-90 lbs. really should not exceed a slender weight of 100. My sis had nice dogs that WERE genuinely about 110 lbs. Too big, but at least they were proportionate and were not fat.
That big GS I saw was well proportioned. I can’t say there was no Mal in it, but it was not obvious.
I’m glad he was friendly. If not, I’d just about as soon take on an Alaskan Grey Wolf...