No one ever qualifies for 0%. My Dad was looking at a Dmax, with perfect credit (like zero debt, house, vehicles, everything paid for) didn't qualify. I've never known anyone to get 0%. Best thing to do is not finance it thru GM. Do it through your bank, walk into the dealership and cut them a check. The price will drop real fast then. My truck dropped about 6k under sticker doing that.
The owner of my dealership told me I could save 1k more by finanacing through GM, getting their discount, then refinancing a month later. I didn't do it.
1969 Chevy RCLB C10 350/TH400 SOLD
2007 Chevy RCSB 4.8 4x4 LS SOLD
2008 Chevy RCSB 5.3 4x4 LT SOLD
2010 Chevy CCSB 6.2 4x4 LT SOLD
2005 GMC CCLB DRW 6.6 Duramax 4x4 191,000 and counting
2013 FORD CCSB F350 6.7 Powerstroke 4x4