I didn't have any problem getting dupes made.

I think it just depends on whether the shop stocks the MB blanks. Try a larger shop. I got mine in a local hardware store. Hey, call ahead and see if they have them.

I didn't get the steel blanks, however. I think only MB stocks them. I've heard that the brass blanks are harder on the ignition - perhaps the brass particles that wear off foul the lock.

It may be better to go to the trouble and expense to get steel keys from the MB dealer. (I've heard they'll require your registration/proof of ownership.)