In the beginning of Season 2 of Warehouse 13 (Episode 201. Time will tell), Leena posing as Claudia debronzes H.G. Wells. And afterwards Wells (with a blanket over her head) is seen exiting the Warehouse along with McPherson, and he says:
'Come on, old friend'
This would imply that they know each other, but H.G. Wells was bronzed in 1899. McPherson would've been born at the 1930's at most (I am taking as a reference the age of the actor who plays it. Which is Roger Rees who was born in 1944). So, how exactly do they know each other?