Acadia Door Roller Replacements

Hi, I'm trying to get your opinion on a replacement roller for my acadia sliding doors. These rollers slip into the bottom of the door and don't really fasten in. I was able to pop both of them out to double check on their condition. The one number I was able to see 4178 stamped in one of the units.

Thanks for your help - you have just a terrific web site. Very user friendly!
Eric