M14 McMillan stock

I recently bought what was advertized as a used USMC M14 McMillan stock. The stock is black, slick (no checkering) and made of figerglass. There is a faint sign of a seam on the bottom where it was moulded. It is extreamly beafy and heavy and has the cutout for the full auto selector as well as the routing for the rear lug receiver for which it was intended for. It also has the bolt hole to a attach the rear lug to the stock. Question: How can you tell this is a McMillan stock? It sure seems to be but I don't see any marking anywhere. I have not checked under the buttplate yet. Any suggestions?

Can you take and post pics of it, particularly the inside of it and maybe around the buttplate interior and the mold seams? It should be obvious to some of us that have McMillan stocks after seeing it.

Danny