Picture worth a thousand words..Is it..?

Looks like a typical cast crank, cast piston 318 to me. Is that balancer beveled on the inner edge? Kinda looks that way in the photo. As mentioned, I'd check the bearing clearances before putting the pan back on....except for the rear main unless it's leaking, or, you feel like resealing that. If the other mains are correct, I'd assume the rear is too.