The increased competitiveness of the job market in recent times means an increased importance for checking the small details. A detail that is often times overlooked is the exact dates you mark for your previous employers.
When companies are considering you for a position and do a background check, seeing conflicting reported dates can be an immediate dis-qualifier, despite any circumstances. It is important to double check with your previous employer and make sure that your dates are matching on your resume, your job application, your linkedIn profile,  and according to you references.
Doing this simple task can provide extra insurance to help decrease the possibility of being eliminated for a miscommunication or lack of attention to a small detail.