I had an early Super Grade that was marked Super Grade on the Floorplate and barrel. It had no black foreend tip
I had one in. 338 WM and it had standard sling studs vice the recessed ones on my P64 SG and was roll marked Super Grade and had it on the floor plate. The stock was shaped the same as the P64 SG I have but as I recall it did not have a black forend.
Times were odd at Winchester then so who knows what escaped from factory captivity but I'd be suspicious.