I'll check with the GM dealer I use, later this week.
They do enough truck mods for customers that I expect they will know about this issue.
2018 L5P Sierra 4x4 SB Denali
Sold 2011 LML Sierra 4x4 CCSB SLT
Sold 2010 LMM Sierra 4x4 CCSB SLT
Sold 2004.5 LLY Sierra 4x4 ECLB SLE