The wording used to describe the process of choosing an upgrade to those
newer Mac computers is accurate and not some hidden meaning. So you
get what you paid for, the option is to choose a different model or select a
higher spec in the build-to-order custom part of the online Apple store...
Same with a MacBook Air, or MacBook Pro (except the non-retina low-end)
and similar to models of iMac that also carefully specify their specifications.
If you are in the US or other country that allows a return within 14 days, and
if you bought the computer from an official Apple Store, you can return it. If
you instead, bought it from an independent reseller of Apple product, you have
only whatever choices they imply before and after you bought it. Some do not
accept returns unless they are DOA or fail to function immediately on delivery.
So hopefully you have some recourse to a situation where whatever the item
was, did not appear to be what you needed at a later time, after purchase.
Good luck & happy computing! 🙂