Wow, I feel like a really big bonehead right about now. So the part numbers on my other post are still correct, and the rails for the R210ii will not work on the R200 (as you already found out). i called our spare parts dept and they told me what I show above, that FJ451 and GJ181 were the rails kits for the R200. I called 866-456-0827, the automated voice said what do I need, and I said "parts". Then it said for for home or business use, and I said Business, then it asked if I was calling on behalf of a business with less than 10 employees and I said Yes. I was connected to Ann, and she confirmed we have (4) of the FJ451 and (7) of the GJ181. if  you have customer number, you might get routed to a different place, but we have the rails for sure. Do you know what part number they are sending you?
I ordered Ready Rails from Dell last week.  I have a PowerEdge R200 server and actually ordered 2 sets since I have a few of those servers.  The rails they sent were Item #330-6301 or the box says PN #0C597M.  These don't seem to be for the R200 server as the knobs on the server are too large for the rails to attach too, they line up perfect, but it just seems like it's wrong.  My dell rep checked and was told these are the right ones, just wondering if anyone knows of a different set of rails that will work for this server? 
Rail Kit for PowerEdge R200