Smith and Wesson's model numbers don't always tell the full story. If the shop simply has it marked as a SW1911SC it could still be a couple of things but more than likely it's NOT an officer's size 1911.
Does it look like any of these?
If it looks like any of the ones with scalloped serrations and a round butt then it's a Commander sized 1911. There are a lot of size variations now and people keep making up new stuff, but Government and Commander have the same grip length in terms of capacity. Officer's sized frames are 1 round shorter. You can run longer mags in them, but without some kind of stop on the magazine itself, if you slam a lot of longer magazines home on an open slide you're slamming rounds in to your ejector and you're likely to knock it loose.
My first commander sized gun was a S&W 1911PD that utilized the scandium allow frame as well. It was a fairly loose fitting gun, but it never failed me and was comfortable to carry. The current SW1911SC models are just a nice improvement on that line. I personally don't care for a round butt or the scalloped serrations, but there's function to everything. And I would rather own any S&W 1911 over just about all of the Kimbers.
If you're getting in to a S&W scandium framed 1911
and it's got crimson trace laser grips for $500 then you're probably doing fine.
You're going to get hosed on trade-in on your Kimber, but that's just how trade in works. If you can afford both I'd get the S&W and then sell your Kimber privately for maximum dollarage.