Looking at the Accuride on-line catalog, their 10 lug x 7.25" circle Chevy/GMC light truck 19.5 looks exactly like these.
My guess is same as yours.
They appear to be 19.5" Accuride GM 10 lug wheels in all details I can see in the pictures.
Who knows what he did to get them to fit, be it bore the holes out for larger studs, and or countersink them to make them stud piloted? Whatever he did I don't think it's a great idea, the centers are not very thick at the bolt holes, as part of the GM system they used clamp plates to spread the load farther away from the nuts.
The ford superduty wheels that use washer nuts have about twice the thickness at the bolt holes.. I'd be concerned that the wheels may crack or pull apart around the studs eventually.
Grigg
