Paul to Seneca (II)

I was happy to receive your letter yesterday. I could have answered it at once if I had had the young man at hand whom I intended to send to you. You well know when and through whom, at what time and to whom something ought to be given for transmission. I beg you therefore not to think yourself neglected, while I have regard to the trustworthiness of the person. ...

So I was wondering whether I could use this as one aspect of the reception historical evidence for Paul as a user of letter carriers. My caution would be that these letters (4th cent. AD pseudonymous collection) exhibit several other epistolary commonplaces, so it might not offer evidence of anything other than an author sprinkling his compositions with authentic sounding epistolary themes.