H1 Stamping with client letter nine months old

I am traveling to India(home country) and will have H1B stamping done. My H1B visa is valid till April 2016.I work on client side and there are two layers between my employer and client i work for.Client does not have the policy to issue client letter for H1B stamping. It only gives client letter in case of RFE which i got on Feb 2015 when my employer filed for my amendment when i joined this project.Can i use that letter as client letter even though its nine months old at the time of interview?

I think you can use that and just in case for any questions araises, try to tell them that you are with the same client in same project.