Every kit comes from a different wafer for the most part, even if they are the same specs on the label. The ASUS Crosshair VII Hero is a pretty darn great motherboard though and has a pretty broad QVL regarding compatible RAM (and lots of RAM not listed to boot). 9 times out of ten there will not be an issue if the first pair works fine. I would not worry about it, especially if you are buying decent budget or better Samsung b-die RAM (You can get decent cheap kits for <$100 USD, so I assume you are). If you want to check, there are numerous "Samsung B die finder pages like this one:
https://benzhaomin.github.io/bdiefinder/ that give you an easy way to look, though some newer models you may have to google search for the specs; ei G-Skill Aegis 3000/3200 Cl 14/15/16 are not listed but are compatible with every board I have tested them on, from horrific Beachwood A320s (HP super budget boards) to the decent
Gigabyte GA-AB350 high quality value types to the top of the line X399 Gigabyte Aorus Extreme, and about 10 other boards in between. Oddly enough, I have not tested them on your board, but here is the QVL for the ASUS Crosshair VII:
http://dlcdnet.asus.com/pub/ASUS/mb...60.101634920.1524872005-1382516923.1524872005
Best of luck.