When I had my 2014 F-250 I had the Firestone Ride-Rite Airbags. They helped keep the truck riding level. When I switched over to my new 2017 F-350 DRW it was obvious after the first tow that I did not need to add bags. I just purchased a new Montana HC 385BR with a dry pin weight of 2660 and it rides level (pic below).
Its just my opinion, but I don't think that you will need to add bags. However, if it makes you feel better, then absolutely go for it.
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2018 Montana High Country 385BR
2017 Ford F-350 DRW 6.7L PSD
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