Least hairy were the 1950's. Just check out the vintage "male nude models" of that period. All muscles, usually standing akimbo, oiled down and shining.
Most hairy was 1970 to 1978 when porn stars such as Harry Reems proudly showed their hairy butts (Deep Throat, The Devil in Miss Jones, et al) and carpeted chests. It was the era of BIG moustaches and "the clone" look along the Castro and in Greenwich Village in the gay community. But in 1978 men were shaving their beards and trying to look like a cadre of less hairy young actors that started with Kevin Kline, Jeff Goldblum, Kevin Costner, and Tom Barringer (who were already too old for "Hollywood"). The hairless male look would eventually focus on the "Brat Pack" five years later consisting of Charley Sheen, Judd Nelson, Emilio Estevez, Anthony Michael Hall, Rob Lowe or anyone that might consider Molly Ringwald's panties worth exploring. This has continued through the last two decades.
I'd still take Walter Houston, as the crazed, woolly and wiry old-timer in Treasure of the Sierra Madre in lieu of any of the previous actors.
Fortunately, body hair is making a comeback. But I'm am an admirer of Bear Kulture and am married to one.