Marlin Model "5"???

Last week I bought a 1985 Model 60 from a buddy.The other night while mounting an old K3 I had layin' around and giving it a good cleaning I noticed (w/my glasses on)that it reads "Model 5".I've had three other people (w/better eyes than mine)look at it and all agree that it looks like a "5",even under magnification.

What gives[?]

Mis-stamped?

One of a kind model that's worth a gazillion dollars[?](yeah right)

Thanks,
BW(the stumped)

IT'S WHAT PEOPLE KNOW ABOUT THEMSELVES THAT MAKES THEM AFRAID.