They won't have that in the store. The store near me only carries the basic configurations listed on apple's website along with a fully loaded version with, I think, a fully loaded version with a 512GB SSD.
These days, they don't want to deal with INVENTORY. U know, stuff and sits there just waiting for the customer to buy. It cost to make them, it cost to ship them, it cost to store them. Modern business are JUST-IN-TIME based. Meaning they maintain a minimum inventory and make it as customers need it.
I bought the same model and wanted to pick it up in store so I ordered it online and selected in store pick up. Worked out well. It even arrived sooner that originally estimated.