I do not have C17 in my book but it looks to be an interior code. The scheduled production date is on the fender tag. 2nd line up, next to the sequence number. Its a 3 digit code. Month then day. Oct-Dec used letters. A01 = Oct 1st, B01 = Dec 1st, C01 = Dec 1st. the rest are 1-9 as the calender...