See the OSHA Interpretation titled Hazard Communication Standard and Material Safety Data Sheets.
That really depends on how SDS's are handled at your organization.
If your employer uses a software program or Internet subscription service for SDS's then maybe not (check with your supervisor, the answer depends on what state and federal agencies have jurisdiction, see also the section on paperless compliance below.).
If the copies you received are exact duplicates (and not updated ones) of sheets that you already have in your "readily accessible" SDS collection, then there is no requirement to keep the extra copies on hand.
However, be sure to carefully check the revision dates on your sheets to make sure there haven't been any changes/updates that you might otherwise overlook!
In some cases, SDS's may be a part of your OSHA-mandated "employee exposure records" and you would have to retain these for at least 30 years.
See OSHA's policy interpretation titled "Retention requirements for superseded MSDSs" for more information.
Also see our FAQ entry What are my rights to an SDS?
And should you receive an updated sheet, then be sure to read the question, "Can I throw away old or outdated MSDS's?
" for information on what to do with the old sheet. SDS's must be specific to the manufacturer and contain the contact information for the "responsible party".