Yeah, I got the letter on the 25th telling me I had a two week free subscription on the RCD-510 that came with our 2010 Jetta. That RCD-510 had Sirius ESN 032250685910 as stated on the Sirius letter.
Trouble is that I sold that RCD-510 after I installed an RNS-510 (at which time I got three months free Sirius). So the buyer of the RCD-510 got the two free weeks, and I got zip.
And yes, I did tell Sirius that I sold the radio....four times. And they would add the new radio to my account, but never remove the old radio. Eventually they removed both radios from the account when I look on-line. Apparently their bookkeeping is screwy because they still associate the old radio with my car.