Yeah, the four bumps is what I'm referring to about being different, some I have are more round looking bumps than the others which are kinda rectangular. I looked last night again and if I remember right the round type say Ford on em and the ones with the rectangular bumps say KH , as in Kelsey Hayes, I'm thinkin this is the main difference. One of the rims with the round bumps also has 12 10 40 on it. Thinking this might be a build date which would also lead me to believe it would have come on a 41 and not a forty, Not sure, but I think I know what you mean about the pyramid, I'll look again when I get home and let you know, either way I should have what you need as I have about 7 4in rims and a few more I haven't checked yet.