H1b cap exempt-lawyer says stamping/travelling to US needed

Hi,

I have an approved h1b petition from my previous employer, its not stamped. When i asked my new company to file under cap exempt using this petition copy,My new companys lawyer is a member of “IALA -American Immigration Lawyers Association” and says i would need a stamping and should have been in US through my previous company to file under cap exempt. Is this true?