The visa defines a range of dates under which you may lawfully enter. Having a visa stamped before you enter to start your job is not a problem -- you are not supposed to enter until you and your employer are ready to start work.
The visa defines a range of dates under which you may lawfully enter. Having a visa stamped before you enter to start your job is not a problem -- you are not supposed to enter until you and your employer are ready to start work.