roller for mirrored closet door

I'm trying to find a part for my mom's mirrored closet doors these brackets were only hooked on one side. They do not have any markings on them. Someone has replaced the rollers on her other doors and it appears they used Cox part number 21-717 21-767. The only thing we need is the plastic wheel if it will snap on.

Let me know if you need more photos.

Thanks for your help !
Tracy