I found out a few weeks back from my dealership that I had a leaking valve. I plan on purchasing from the dealership the oem replacement valve cover left and right tommorrow. Should I also purchase the valve cover gaskets?

 

I would have definitely started with replacing just the gaskets... But yes, you need to replace both.

 

^depends if the leak is from the outter gasket or the spark plugs. but OP didnt specify

 

There is no reason to change the valve covers for now, just change both valve gaskets. The gaskets act as a seal for the engine. But if your spark plug is contaminated with oil, you need to change the valve covers which can be expensive.