Help identifying white sole boots?

I was watching this interview with John Mayer and was struck by the boots that Don Was, his producer, is wearing (on the left). Anyone able to ID these? Seems like a very distinctive sole. 

At first I thought it was a Red Wing Pecos or something of the like. 

Nailed it! The sole exactly matches Generic Surplus. Unfortunately, these must be an older model. Still looking for a match there. THANK YOU!