Yeah there is, but you might think I'm yanking your chain. You can trigger the 'confirmation mode' and the body ECU will tell you by clicking the locks up and down how many key fobs are enabled on your system. It clicks five times if none are enabled. Ready for this?:
Key out, driver door open&unlocked, all others closed.
Insert key in ignition and remove(do not turn).
Go Lock/Unlock five times on driver door pad, 1 sec between each push. Close door and open. repeat lock/unlock 5 times as above. Insert key. Turn key Lock/On/Lock/On/Lock/On/Lock/On/Lock with 1 sec between turns. Pull out key. The locks should do their thing. Or, add one more on/lock in next to last step and ECU will lock out all wireless key fobs and click locks 5 times to confirm(prohibition mode). Source: Volume 2; 1999 Toyota 4Runner Repair Manual (FSM) pages BE-90 to BE-92. Presumably, if you don't have keyless entry, the locks won't click at the end and the car will think you are nuts. My '99 SR5 has the keyless entry system with no intrusion alarm.