He's a metal worker sort of guy, not sure where he picked it up, it appears to be new'ish or at the very least, well kept miles. Says he'll weld in the necessary nipple to hook up to the pump.

A bit of inspection and info from CharlieJ indicates it's a 3 7/8 gallon ex Pearl Beer container from San Antonio. The top is a triple ribbed rubber twist type much like the drain hole plugs of boats.

The holes would take a long #10 fabricated SS bolt threaded each end and it could be attached to a bulkhead.