Welcome to the forum! I would have hoped your first request was an easy one like a set of brake pads

lol
Unfortunately you are correct in that Mopar does not offer a hardware kit separate for this accessory however there are aftermarket solutions to get this deflector mounted. One alternative is to use a Rubber Wellnut , See this link for examples
https://www.google.com/search?q=rub...4-XlAhVErp4KHaP0BmUQ_AUIEygC&biw=1396&bih=657
These nuts expand when tightened down and probably work better than the factory plastic clip, Infact some deflector companies use this method as OE. You would need to measure the hole opening and order the appropriate size and hardware as well.
Please let me know if you have any other questions.
Thanks,
-Benny