First, do you have a policy concerning calibration intervals? Do you have a policy concerning "in service "dates? You will need to comply with these.
If you don't have these policies, a lot will depend on the certificate. Does it have a calibration due date assigned? Does it state anything about "in service" dates. Without your own policy you should be following the OEM's.
Does the certificate actually state that this set passed calibration and the measurements are traceable to a national lab? A lot of these retail certs are certificates of conformance only, they tell you that you got what you bought.
And yes, pin gauges can and do change size with age, especially less expensive sets that do not get full treatment to stabilize their crystal structure. It usually will take more than two years, but who knows unless you verify them.