307 of that age has the PIN code stored in the bsi unit which is also the immobiliser you would need a specialist such as 3D or Hickleys to EEPROM the bsi to read the key dump to either extract the PIN or code a new chip if there is a key that needs writing in, that's a take the bsi out and do on the bench job.
Zed Full diagnostics can extract the PIN from later CAN, flick key type PSA Bsi through the diagnostic socket, but yours is too early.
Alternative is to order the PIN from Peugeot and pay 25 quid, it's not that bad, I can get the PIN codes through key suppliers but in both cases there is a need to prove the identity of the car.