Better safe then sorry, If you're running an
antifreeze/water mix for your cooling system then I'd recover some of the froth and have it lab tested for glycol content. If it's present then it's not condensation. Additionally, I'd probably run a coolant system pressure test before the results came back. You also might pull a valve cover to see what's inside.
BTW... I taste tested my "froth" to determine glycol content, no lab required.
http://clubcobra.com/forums/showthread.php?t=105684