Best Years for the 318 LA?

As far as a premium 318 that’s supposed to be a step above the others is the early 70s -3 318. Heavy duty truck, industrial, marine application. It’s supposed to be marked with a -3 on one of the VIN pads and has a premium forged steel shotpeened & flame hardened (maybe TuffRided, too?) crankshaft. I’m a little fuzzy on this next detail at the moment so hopefully someone will chime in if I’m wrong. It’s my understanding that you would need to check if it were a reverse rotation (counterclockwise) engine such as marine applications because the oil seal surface grooves on the #5 crank crank journal have to be recut in the opposite direction for it not to leak if converted to clockwise (viewed from the front) rotation.