Is old i797 mandatory for a new H1-B cap-exempt petition?

H-1B Visa: I have an approved h1b petition applied in the year 2012, but it was given 221(g) by Visa Officer. Now I got a new employer who wants to file a cap-exempt petition for me. The issue is I somewhere lost my i-797 but I have all the other related docs including i129, LCA and Receipt Number.Can my new employer file a cap-exempt petition with these docs or should I get a duplicate i797 from my old employer?

Its not a must but without it(or its number etc) its less likely that the officer would be able to consider under non-CAP. If you want to try, you have to provide as much information as you can about the previous approval.