Features of the acorns would probably help determine if it is a foliage variant or actually an unexpected species.

Compare with Quercus laurifolia

Those leaves appear narrower than the shingle oaks I'm familiar with. I believe willow oak's native range comes pretty close to the west MD mountains? Laurel oak's native range doesn't reach that far north.

Agree that the few arboretum shingle oaks I've seen had somewhat bigger, wider leaves. WAY too far north here for laurel oak. Acorns I saw were just getting going, so have to wait till fall for mature ones. Below is willow oak's range from Silvics Manual -- as you can see they avoid the Appalachian Mnts. No way this is wild willow oak (they grow OK here when planted, but I've seen none here within 15 miles & the ones I see are of course in people's yards or highway medians).

Edit: Shingle oak range from wiki -- comes right into my location, tho avoids Garrett Co, MD (westernmost MD Co), just to my west:

These range maps are generally based on the trees native range, and does not necessarily mean it will not grow in your area. We have a Nuttal Oak growing in our front yard that is doing great, nearly doubling in size in 9 years. However that native range is the lower Mississippi Valley .

From what I have read the Raleigh NC area is similar to the areas in its native range where the tree is found.