If it's a later block, it's gonna be a 1 piece which seals WAY better. It's metal coated in a rubber polymer, typical round seal. Spring goes towards the oil. USMC nailed it, go FelPro or Mr. Gasket. You can get a FelPro at your local Autozone, Advance, etc etc.
If you do find out you need a 2 piece, DO NOT put the gaps in line with the block/oil pan flange. Rotate it almost 45* so the seams are up in the block, and down in the oil pan.