You need to know if the remote audit logs will contain TLS transfer information.
Remote logging of Message Audit Logs for Messaging Gateway include cipher information for receiving and sending of a message with TLS.
This is an example of what the Message Audit Log remote logging looks like specific to each direction:
<158>Feb 16 21:53:20 smgccs ecelerity[41115]: 1645077200|c0a86419-844477000000a09b-05-620de2cfa18b|TLS_RECEIVED|ecdhe-rsa-aes256-gcm-sha384
<158>Feb 16 21:53:56 smgccs ecelerity[41115]: 1645077236|c0a86419-8644b7000000a09b-06-620de2f0c5c3|TLS_DELIVERY|ecdhe-rsa-aes256-gcm-sha384