Yes it is configurable, mine (an 86) only the drivers door unlocked with the smart entry. I changed it to both doors with this method (credit to codename47 as it was from his post):
Use the drivers door handle to open the door
Leave the door open and hold the lock and unlock buttons on the fob for 5 seconds
You'll hear a couple of beeps
Voila - your drives handle now opens both doors.
This can be repeated to reverse if wanted!