Have you tried contacting Dell sales via chat and seeing what they have available? 

https://www.dell.com/support/assets-transfer/us/en/04/#/Identify

Here are all the available OEM part numbers for the R12 HyperX:  https://www.dell.com/community/Alienware-Desktops/FAQ-Aurora-R12/m-p/7844516

My apologies, I should have included that in my original post. Yes, I did contact Dell and they do have memory that they can sell me but aren't sure if it's Kingston HyperX memory. I spoke with Sharanya (stellar customer service by the way) and asked her to confirm that they were Kingston sticks with the heat spreaders but she had to ask another team. Sounds like it isn't Kingston memory, instead just regular memory with green PCB and no heat spreader.

Also, if possible, you might consider asking Dell to do a warranty and ownership transfer. 

Ah, usually they are able to look up the part numbers based on your service tag to get the right HyperX OEM RAM, but the R11/12 sticks are sometimes in short supply.  

One other thing to mention, is that they don't sell it stock with 8 x 4 = 32 GB RAM, they sell it stock with 2 x 16 = 32 GB RAM when new, so it's not officially validated in a 4 x 8 GB configuration (which isn't to say it won't necessarily  work). 

What I'm really looking for here is to use what I currently have and maintain all out of the box functionality with overclocking. Some are saying you might have to get rid of the factory memory and buy all new stuff. I'm not opposed to this but would rather save money if possible.

The OEM parts are very specific

Your pair is  XW21KG-MIE2

https://www.ebay.com/itm/234001789876

https://www.impactcomputers.com/w21kg.html

Validated OEM memory =
Four slots
128GB maximum
6TCK6 32GB HyperX Fury XMP DDR4, 3400MHz, Unbuffered, 288 pin, Dual Rank, 1.25V, Non-ECC, Kingston X6TCK6-MIE, X6TCK6-HYA
VTW4H 32GB HyperX Fury XMP DDR4, 3200MHz, Unbuffered, 288 pin, Dual Rank, 1.25V, Non-ECC, Kingston XVTW4H-MIE
JV223 16GB HyperX Fury XMP DDR4, 3400MHz, Unbuffered, 288 pin, Single Rank, 1.35V, Non-ECC, Kingston XJV223-HYA, XJV223-MIE
K2M26 16GB HyperX Fury XMP DDR4, 3400MHz, Unbuffered, 288 pin, Single Rank, 1.35V, Non-ECC, Kingston XK2M26-MIE
2YH1K 16GB HyperX Fury XMP DDR4, 3200MHz, Unbuffered, 288 pin, Single Rank, 1.25V, Non-ECC, Kingston X2YH1K-HYA, X2YH1K-MIE
W21KG 8GB HyperX Fury XMP DDR4, 3200MHz, Unbuffered, 288 pin, Single Rank, 1.25V, Non-ECC, Kingston XW21KG-HYD2, XW21KG-MIE, XW21KG-MIE2

So long as I find a pair with the matching XW21KG-MIE2 number I should be good, right? Also, would you have any insight as to how I should pair the memory? I was planning on doing 8GB X4 but it sounds like that configuration might not be supported. If it won't work then I may as well replace it all with 16GB sticks and get four of them.

Thanks