My next question for the paint guys is would the gold on the valve covers be able to handle the high engine temperature?
Pretty much any catalyzed paint, enamel or urethane in either single stage or 2/3 stage paints will hold up to engine temperatures much better than any spray can will. If you don't need a specific paint code, you can also get catalyzed high temperature paints from PPG, DuPont, Valspar and Sherwin/Martin. I'm sure there are others, but those are high temp paints I've sprayed before.
Take an temp measurement of your hood or roof skin after it's been parked outside on a hot summer day and you won't worry about your valve cover temp anymore! Especially if it's a dark color.