Probably not. Typically if the phones are in SRST mode, your remote site is not connected to CUCM. If its not connected to CUCM, then possibly your WAN link is down and CUOM will not be able to pole for information about the phones/gateway.
You can setup a trigger in RTMT (Or CUOM) and link gateway/phone de-registration. If they happen together, you know the site went into SRST mode.