Orangecicle, why would you think that new head gaskets REQUIRE resurfacing of the heads, and why would you think that removing the piston/rings from the cylinders then REQUIREs ring replacement?
As for the OP's question, a compression and/or leakdown test will tell you if you have a blown head gasket, but I'd be sure the water pump seals have not let go, and that the cooling system's integrity has not been compromised first. A leak will allow the system to depressurize, not to mention things like a bubble forming in the rear head due to low levels. Due to the design of the engine, if the coolant level drops low enough, an air pocket is formed in the rear head, which when it gets hot enough, expands and pushes fluid out of the radiator.
Run the bike for a few minutes then pull the outer clutch cover. Got milkshake? Rebuild the water pump. Also, check the oil filter. Wavy pleats could mean water contamination in the oil.
Said James to Red Molly, Now Nortons and Greeves and Indians won't do- they don't have a soul like a Vincent '52