I thought SerVess was the house brand of True Value hardware, so I doubt they made them themselves, but paid someone else to private label them. Not knowing squat about pipe wrenches, or where the spring goes, I imagine you could find a spring for any old pipe wrench, and with a little tweaking it might work. Or find someone with one, and ask for a picture.
But I doubt you will find one at retail bearing the SerVess name.