http://www.ebay.com/itm/Gulf-Porcelain-H...e-/180813387704...from '2curios'...the porcelain looks thick, lots of shelving...but the lettering below 'OIL' looks VERY suspect to me...and the white outer border is wider than on any Gulf flange sign in this style, that I've seen...I just don't think it's 'right'...
...top photo is the sign in question, from '2curios' auction - the other one from an old Proxibid listing (which is definitely an old one)...note the differences...what do y'all think?