Hey Scott. I notice one detail that is lacking in yours and the one in the link you posted. Look at the tail, the lines run together unlike this one which seems more uniformed.
This is my keyhole sign but if you look in the Mobil collectors guide, there is one from Dave Mercers collection pictured as well and you can see the same tail details as the one I posted.
Also look at an old auction too, look at its tail. I believe this sign is the real deal also.
eBay number: 330846685335
Hope that helps some.
