SajinBoth 08G-P4-5170 & 08G-P4-6173 use the same reference PCB.
ARIOS-X1 you can find custom water cooled backplates there. You don't need to have a waterblock for them to be mounted and if you decided to get one be sure to ask them to include a mounting mechanism kit along with it so you can have the screws you need to secure it. I have a nickel one for my 1070 FTW without a waterblock, just used the longer screws from the mount kit. These a made from like 2mm of aluminum and are much stronger support than the ones EVGA come with, no flex at all very solid with also a thermal pad for PCB VRM/GPU cooling. It won't let the PCB sag over time if it ever would end up so. I'll attach a pic of mine so you can get an idea." />