The pignut I am using is quite white and I am getting it directly from the sawyer; no confusion about what it is. The bark slabs were still in the firewood pile. If they hadn't been buried under tons (literally) of other wood he would have given them to me. He is setting aside the bark slabs from some other large hickory logs he has on the ground now. They are the first cuts to square the logs; worthless for lumber, but there are plenty of staves in them. Anyway, the boards I got are outermost flat sawn, as close to stave wood as I could get in a board. I don't know if the heartwood is any darker. I didn't pick through the pile; he did, using my criteria. I was lucky enough to find a local sawyer interested in bows and he was trying to give me the best wood for it. He even gave me a 64" long 2"x6" slab of persimmon that had bark on the corners to try. When I go back for hickory bark slabs, I hope to have a persimmon bow for him.
BTW, for point of reference for you semi-locals in NC and VA, his price on hickory is $1.25/BF even in piddlin' quantities (like one 8' 1"x6" for $5; I bought 4, but he would have sold me just 1). He is just north of Raleigh.