GMC Sierra 1500 input

My BIL is looking to lease a GMC Sierra 1500 Denali and any help or input would be appreciated. Just looking in the Signed section and Marketplace, there is very little to work off of. I presume that is because they are a pay to play vehicle. Having said that, does anyone have input on what a fair ask would be for a pre-incentive discount?

Also, is it correct that GM does not have an acquisition fee?