Just for conversation ... personally I'd address a 3" nose high setup by whatever it took on my own fiver but granted you do see lotsa late model pickup / fiver combinations pulling in that configuration on most any hiway. As a rebuttal which I'm know for ... we've added 3" blocks to a 35' Forest River product a while back and it did raise the front A/C almost an inch. I wasn't onboard with the owner's decision, but money talks and hot air walks. A lifted truck so you can see down at the gals with mini skirts on in the car next to you just doesn't have the bling it used to for me.
I will point out it all depends on how far forward the A/C is and where the axles are located as to overall height increase. The front A/C on this unit was a fat 6' back from the pin box pin itself. That distance probably made the @1" happen which like you elude to isn't worth straining brain cells over but it does raise the center of gravity overall which I'd rather avoid.