It sounds like you've got the newer style fog lamps, which have a little square-ish bezel around them and are smaller in diameter than the older style. These newer style look like so:Yea i just grabbed photos from google for this - its the Bezel itself, realizing that the LTD model uses a different light for the fog light systems.
If so, you will want the older-style fog lamp trim, which is what's in your top image above. Assuming you have the correct brackets with your SS3s, they will fit in the older-style bezels just fine, though a small amount of the lens around the perimeter is covered up:
When I installed my SS3s, I got the bezels off eBay and was able to find them on there pretty cheap.