x3270 3.2 itself does not use dates or absolute times, except for adding timestamps to optional logs.
x3270 3.2 does manipulate small relative time intervals, for the purpose of timing out connection requests and other internal operations. These depend on system facilities which may have inherent overflow problems (such as a Unix timestamp overflowing at 2^32 seconds past 1/1/1970), but none are Y2K-sensitive.
Beyond that, x3270 3.2 may fall victim to Y2K problems in the local OS, C library, X windows libraries, or X server.