FE heads can be used on either side.
Head gaskets are identical. They simply flip over but 'front' always remains in the front. Heads follow the same assembly as rocker shafts where the pair have no LH or RH. FE pistons, rods and bearings are not 'hand' specific except on the MEL 430 where the original domed pistons are in two sets of, four RH and four LH.