Not usually. For most individuals, once the gyno is gone it tends to stay away until something happens to trigger gyno growth again - i.e. using test without an AI.
I did my first cycle recently of just test and didn't use a AI.. I started to get sore nipples in week 9 or 10... letro + nolva cured it.
I am going to do a 2nd cycle soon of test + EQ... this time I want to make sure I use an AI.. can I do .25/EOD of letro without it adversely affecting my gains?