To quote ED (colortuffs.com) from 2006 over on VBMX
In the sorta-early 80's, Mongoose had both Motomags AND Skyway Tuffs spec'd on their complete bikes that you could buy at your local bike shop. For a couple of years, if you bought a Mongoose with the Tuff Wheel option, you got what was called the "Mongoose Approved Skyway Tuff Wheel", with the Maurice the Mongoose stamp on the wheel.
There were quite a few of these made, but I'm sure that not too many are in the condition that you have. I don't think that the Mongoose stamp increases the value of the wheel, but the fact that you have alloyed hubbed Tuff Wheel has become sort of a rarity in itself.
Enjoy them!