I did some more research, here's the parts list for the recall:
is additive included in seal recall? - Cadillac Owners
Part Number - Description
19179933 - Seal Kit, Diff Drv P/Gr (CTS, STS, SRX, Solstice, SKY, GT) (Note: STS AWD & SRX AWD will also require P/N 19179936)
19179934 - Seal Kit, Diff Drv P/Gr (STS-V, CTS-V)
19179936 - Seal Kit, Frt Diff Drv P/Gr (STS AWD, SRX AWD) (Note: STS AWD & SRX AWD will also require P/N 19179933)
89021677 - Lubricant, Gr Synthetic, SAE 75W-90
01052358 - Lubricant, Limited-Slip Differential (if needed)
Looks like the dealer almost certainly made a mistake. Thank goodness I have a night to sleep on it, because I'm pretty angry right now.
Here's the million dollar question, though. How much damage did I do to my new differential by running it with no friction modifier? I went about 10 or 15 miles, going as fast as 80 mph on the highway and in stop and go traffic. I probably operated the vehicle for about 30 minutes.
This car has been nothing but one incredible headache since I bought it in June.
