Does the color mean anything? Or is it just aesthetics?

I have had 2 sticks of this in my PC for about 7 or 8 years

https://www.corsair.com/us/en/p/memory/CMK16GX4M2A2133C13R/vengeancea-lpx-16gb-2-x-8gb-ddr4-dram-2133mhz-c13-memory-kit-red-cmk16gx4m2a2133c13r

And I decided recently to buy more ram to upgrade my system a little bit so I purchased this from ebay

https://i.imgur.com/Ck75hVE.png (Sorry for the quality- its the image from the listing)

Which appears to be 2 out of the 4 sticks that originally came with a 4 stick kit but is otherwise the same specifications as mine

My thinking on buying it was, that the color was just for aesthetic reasons and that I could use it with no issues, but someone I know recently told me that its a bad idea to mix ram from different kits

I’m currently running my 2x8GB sticks in duel channel, so I planned to put the new black sticks in the remaining slots, if what I’m trying to do is okay to do, is this the way to do it as well?