Actually, I believe they are one and the same. A locksmith works on any type of lock.
What's The Difference Between a Car Locksmith and a Door Locksmith?
There isn't a difference. A locksmith typically knows how to work with a variety of different locks. Car locks are usually a bit trickier to work with though according to my cousin. He's a locksmith and he tells me about it all the time. It's pretty interesting.