I'd take a picture of it and contact Tredit Tire: http://www.tredittire.com
They've always been very cooperative and sell at good prices. That's most likely where Keystone got the original and so if they're still available they should be able to get you a match.
Dick, Joyce, Diego, Picatso and Gustav
2017 3720 RL, and 2013 HC 343RL
2017 3500 Dodge Maxi DRW 4X4, Pullrite Hitch, IS, Disk Brakes, 3rd AC, Winegard Traveler, Bathroom door mod, Dometic 320, couch for desk swap, etc.