Is it the same fob as your RAM? You'll need the FCC ID from both of them...even if they look like same they might not be compatible.
If they ARE compatible, you might be a good candidate to have it unlocked....someone on the forum bought a tool that advertises it can unlock previously used fobs. Send a PM to
@STecoD if you are interested (you would have to send the fob to him to get it unlocked)
Once it is unlocked, if you have AlfaOBD you can program the fob to your truck using the app and a bluetooth OBD adapter (OBD MX recommended)
Without the app, you could pay a dealer to do it but that kinda defeats the purpose
Im sure you could pay them or a locksmith to unlock it, but Im pretty sure the charge would be typical dealer marked up.