my H1B approved in 2008 and did not go for the stamping

My H1 petition approved in 2008 and I did not go for stamping, later same company filed H1 petition again in 2011 in cap exemption even in 2011 also I have not attended the stamping.

I have unused petition, can I go for the cap exemption now. since first approval was in 2008 so 6 years already crossed.

Thanks in advance.