Appointment Letter Not Issued At The Time Of Joining

Dear All,
Our company is 10 years old. At the time of inception not all the employees have received their offer/ appointment letter. On scrutinizing the files we have realized that company's offer or appointment letter is missing from many files.
In such a situation what should be our course of action.
1) Can we now issue a back dated appointment letter to those employees and how much relevance does it hold legally? OR
2) Should we issue them appointment letter with present date referring their earlier date of joining.
Please suggest.
Regards,

Dear Friend
In this issue you have to see the availablility of the signing authority. If the signing authority is available from the day of the opening of the concern you can issue the letters puttin the exact date in the appointment and get the singature from the authority.
regards
alphonse

Dear Member
Issuing with back dated appointment letter is not appropriated.
Now U can issue appointment letter with present date referring their earlier date of joining.
please think is it necessary to issue appointment letter.
If your organization having certified standing orders, it's enough to take necessary actions against any worker /employee