yes, they will still fit.
some board manufacturers make slightly smaller boards to reduce costs (just like my gigabyte board). all the screw holes will still match up to the backplate though, you will simply have some just off the edge that wont be covered by the mobo.
it looks a little weird sometimes though. my video card actually extends beyond the limit of my mobo :LOL:
i have an old pic of my rig here:
its before i upgraded my GPU, but you can just about make out the little bronzed screw holes next to the mobo, where normally it would screw in place. with the mobo being slightly shorter though, it doesnt need to use them.