I got my $500 coupon in the mail today as well. Unfortunately, I took delivery of my truck on 09/30 so I will be out of luck. The card says it has to be presented at the time of delivery, so I don't think there is much hope of it being honored now.
Mine expires 1/31/14. Mine says, "Certificate must be presented to a participating franchised US Chrysler Group LLC dealer. Certificate must be redeemed at time of purchase or lease of eligible vehicle."