Zipp 303 Firecast 2014 clincher rim brake Carbon wheels worn out?

[John.23D.Cyclist]

Hi, I've had the Zipps for a few years and in the past month started to see the woven ply on the braking surface. It seems like the epoxy layer has worn out but would like to check first before saying goodbye to them. If anyone has had the same problem and could help.
Thanks.