The earliest letter that undoubtedly reached several churches is the letter to the Galatians. Paul and its other senders did not expect this letter to be copied (cf. Gal 6.11).I can see why she might say this, since only the autograph would visually display the large letters in the hand of Paul. But drawing attention verbally to the size of the writing only makes sense if the author understands that most readers won't actually see the large letters, but will hear it read out. This way of verbalising the graphological information actually preserves the autographical feature into the textual tradition (hence Galatians does not get what some other letters in the literary traditions got - editorial notes on the handwriting). So I don't see it as precluding any anticipation of copying. In any case if we take the plural in 1.2 seriously ('to the churches in Galatia'), multiple copies would be envisaged from the outset (as Standhartinger seems to recognise in the first sentence quoted).
NB. For a different take on this see Chris Keith «'In My Own Hand': Grapho-Literacy and the Apostle Paul» Biblica 89 (2008) 39-58 (not to my mind entirely convincingly).