H1-B : Applied for Amendment from India , got I797 with I94

Hi ,My Ex- Employer applied for my First H1-B VISA and was approved , but later they had to file for an amendment for location change(before i even travelled ).When i got the I797 for amendment approval it has I94 also , This means an extension was also applied ? if so, its not possible to apply for extension when im still in india or is it the case we get I94 with I797 if amendment is applied.Should i get initial I797 also from my ex-employer ? or amended I797 is enough.Thanks