After all the originals fell off, I've lost 2 sets of these.G-PLUS 1 Pair for 2011-2016 Dodge Ram 3500 1-Ton Dually Truck Chrome Front Wheel Center Caps 2012 2013 2014 2015 Amazon product ASIN B075VRXHNY
Use the Laramie Caps, they are different built then the Longhorn, they stay on.
Check this not so old thread with pics showing the differences.
https://www.turbodieselregister.com/threads/lost-longhorn-center-cap.265168/
I have a duallyOn ebay, they are often for sale, best is to search with the partnumber.
Everyone that sells OEM has that number in the description, you just sort out the China crap copies then.
For example these >>>>> https://www.ebay.com/itm/2003-2012-...152457&hash=item1cdb92362e:g:LLsAAOSwSxtdqAzg