Hello,
These units have valid lot codes as well.
The difference between SN65C3232DR and SN65C3232EDR relates to their ESD rating. Both are rated for 15 kV (HBM) on the RS-232 signal pins. However, the "E" version has an additional specification for the more-severe IEC 61000-4-2 ESD model (8 kV for contact discharge, 15 kV for air discharge).