The 2.5" 4TB/5TB HDD's mentioned previously also fit in PS4 Pro's as well. It requires opening the PS4 Pro and voiding the warranty, and leaves a slight bump that prevents the hdd cover in the back from snapping in place. However, that is a minor sacrifice to make for internal HDD space.
Congrats on the 4.55, please do share the digit after 969 to help others. Also, MC95XX will be almost impossible now, those were launch units that came with 3.70.
Yeah MC97XX is going to be too new. Ebay is going to be a risk unless the seller provides the serial number to you. Look at my previous post in this thread for S/N info on Pro's and try to find them in local stores. I have come across plenty of them in Target and Gamestop. Not so much luck at...
For anyone hunting PS4 Pro's with 4.55 or less, I have bought two Pro's recently and here are my findings:
Both Pro's were 7015B with the Horizon coming artwork on the back (Do not bother with the newer units with HDR Logo on the top right corner)
S/N MC9696 | Manufactured June 2017 | FW 4.70...