Yes, if Lock AP Configuration is enabled and the AP Group mapped to the device has Auto Sync enabled, cnMaestro will auto-sync the device after it detects that the device configuration has changed. In this case of the customer pressing the reset button, this would be after the device registers back to cnMaestro.
The difference between E-series and R-series is that Auto Sync is disabled by default for R-series AP Groups. You must manually enable this for R-series AP Groups. This will allow locking the AP's configuration and will also automatically push changes made the the AP Group or WLANs to mapped devices after you click Save.
Configuration will be pushed to the device approximately 30 seconds after cnMaestro detect that the device configuration has been changed. In your case this will be when the device re-registers to cnMaestro.
Configuration overrides and user-defined overrides will be respected. The same configuration sent the device when the AP Group was last applied will be sent, unless you made changes since then. This includes device-specific variables, such as your SSID/password variables. The only exception to this rule is Auto-Set network settings for E-series devices, as this will use the latest settings being used by the device.
If this is not working as expected for your cnPilot R devices, please let us know.