We now have replacement LS oil pan gaskets available for $24. Unlikely the factory gasket, which is made like a jigsaw puzzle of 4 pieces, these are made from a single piece of aluminum. The gasket seal is silicon like the factory gasket. Designed using original GM CAD models for a perfect fit.
At $24 bucks these are less costly than the factory gasket and won't give you any sealing issues.
Available here: http://www.improvedracing.com/gasket...nes-p-660.html Single-piece replacement LS oil pan gasket.