If I replace the anti-theft module will it need to be programmed?

Yes, it will need to be programmed here is how the anti-theft module or immobilizer is replaced in the instructions below. Also check the diagrams, in the images below as well.

SKIS INITIALIZATION

The Sentry Key Immobilizer System (SKIS) must be initialized following a Sentry Key Remote Entry Module (SKREEM), sometimes referred to as the Wireless Control Module (WCM), replacement. SKIS initialization requires the use of a diagnostic scan tool. Initialization will also require that you have access to the unique four-digit PIN code that was assigned to the original SKREEM/WCM. The PIN code MUST be used to enter the Secured Access Mode in the SKREEM/WCM. This PIN number may be obtained from the vehicle owner, from the original vehicle invoice, or from the DaimlerChrysler Customer Center See: Alarm Module, (Vehicle Antitheft) > Programming and Relearning > Programming the Sentry Key Remote Entry Module (SKREEM).

NOTE: If a Powertrain Control Module (PCM) is replaced on a vehicle equipped with the Sentry Key Immobilizer System (SKIS), the unique Secret Key data must be transferred from the Sentry Key Remote Entry Module (SKREEM) to the new PCM using the appropriate programming procedure. This procedure also requires the use of a diagnostic scan tool and the unique four-digit PIN code to enter the Secured Access Mode in the SKREEM/WCM.

Check out the diagrams (below). Please let us know what happens.

Good question, you will need to talk to the locksmith, they may have a way around it but that will depend on the locksmith. If not, you are stuck with the dealer which ownership will need to be provided.