Um....well..... when I bought my MBA new at the Apple store I knew that I was specifying that I wanted to purchase a MacBook Air that had the SSD HD with 64 GB and 2 GB RAM. The sales associate brought the box out and it listed the specs on the outside. When I got home and opened it and got the machine up and running yes, I indeed verified that by checking "About This Mac." I also checked the HD capacity before I then removed the OS and reinstalled it.
Apologies here: I have to admit that when I first responded I wasn't thinking that the original poster might be in the process of buying a gently-used MBA from a private party or maybe as a refurb from Apple and of course would want to check and verify the specs on the machine and if he/she is a newcomer/switcher to Mac might not know how to do that.