Installations must meet current regulations whenever you modify a circuit. The requirements tthat were adopted locally when last modified are pretty hard to determine. The 2017 NEC (which is the edition most jurisdictions are now enforcing*) requires "Ground-Fault Circuit-Interrupter" protection for all kitchen receptacles that serve countertop surfaces, and receptacles within 6' of any sink. Undersink receptacles for a disposal or dishwasher would be subject to the 6' rule.
The NEC requirement for protection does not specify a receptacle at every location, or even a receptacle at all. The whole circuit could be protected by a circuit breaker, or the wires feeding a location could be fed from the "load" terminals of another GFCI receptacle. Everything connected to the load terminals of a receptacle behaves just like anything plugged into the front of the receptacle.
Pressing the test buttons on local receptacles or buttons on breakers in your panel may safely interrupt the power, but a tester designed for the purpose is generally works best, and is a one-step method to determine if protected.
*The NFPA (National Fire Protection Association) which owns the NEC has no enforcement authority. States, counties, and even cities can determine when and which edition and modifications to codes they adopt. The 2020 NEC is available now, and slowly beginning to be adopted, but some places are even still using the 2008 edition.