how could I tell if my '01 4Runner is remote entry equipped?

All '01s equipped?

Easiest way is to call a local Toyota dealership and talk to the parts department. Provide them your VIN number and they can confirm if you have keyless entry installed, and if you have the FACTORY or the RS3000 or RS3200 type remote system. You need to know that so you know which type of remote to get.