Dear,
Relieving any employee is not only depend upon, whether notice period served properly or not..?
There are other aspect also affect for the same.e.g. if any dispute with company, if you payable any amount to company, any deductions, Handover the job, documents, files etc. so, once everything will be clear, you may get the relieving letter from company.
Most of the companies are providing the relieving letter post Full & Final Settlement only.
Therefore, check your company policy for more clarity on the same.
Regards,
Tushar Swar