I've looked for a Sage interior wheel too (before the Gallery model came out) and indeed, no regular Camrys came with the leather wheel.
Feel free to take a look at my collection of photos:
http://jeddy.homeip.net/s-match/
Check out ES300-6.jpg and Camry-4.jpg especially.
It looks like the ES300 wheel will drop right in. If you look around, salvage yards should carry it for around $80. Another thing you can try is the Sienna steering wheel -- it looks like it'll also fit, these leather wheels are usually available for a little less, I think around $50.
If you don't feel like taking the risk, you can also check out WheelSkins. You stich a leather cover right over your old wheel. It looks and feels pretty good, only thing is that on a thick steering wheel rim like ours, it will feel *extra* thick. These are orderable from WheelSkins for about $35 I think.