I thought it had to be a c/k 30 to be a crewcab. I found this today.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=110138551961
the badges on the fender say 20 and the vin agrees. did they make K20 crew cabs?
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=110138551961
the badges on the fender say 20 and the vin agrees. did they make K20 crew cabs?

