Shotgun Weaver

Will an “integrated weaver style” red dot scope mount to a Picatinny Rail?

I bought a picatinny rail for my Mossberg 500 tactical shotgun off ebay today… and was interested in putting this scope/red dot sight on top. Its a weaver style scope/red dot sight though, so will it fit?
Here is what I am looking to get: http://cgi.ebay.com/RED-GREEN-DOT-SIGHT-LOW-LIGHT-WEAVER-SCOPE-w-4-RETICLE_W0QQitemZ250315475459QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item250315475459&_trksid=p4634.c0.m14

The slot spacing on the Picatinny rails is a little wider than on the weavers. All the other measurements are the same. So items designed for a picatinny rail sometimes have problems mounting on a weaver, because the cross bar doesn’t fit in the gap. Going the other way around, and it obviously fits just fine, so you’re all set.

mr. weaver shotgun dance-missing