If I understand you right, Suburban had a service 10? Didn't know that, I thought that was marked for a c-10, course it doesn't say fleetside etc like the 1023, which doesn't show for 1971, but it's likely correct anyway. Fun!
Here's the 1022, which shows for 69-72 service 10-30. Couldn't tell you what it's for, but I bet it works. Manual says cut to fit.:
http://shop.docrebuild.com/1955-1991...GM3991022.aspx
Edit, I found this illustration for a 1022.
http://www.discontinuedspares.com/in...ucts_id=435385