Can someone tell me who manufactured these wide 5 wheels?

[speedway]

I have never seen a wheel like this before in 15". It appears to be factory made. Came on the front of a 37 that I bought. Has a little more reverse than a regular 16" wide 5. I removed it from the car to see if there were any stampings or markings, there were none. I have heard that General Jumbo made a wide 5 wheel but have never seen one and could not find one on google. I understand that Lorin Sorensen in Ford Life did a very complete article on accessory wheels but do not have access to that article.