Old racing tip I've used on many applications. Turn the gauge so the needle is in the
up 12 o'clock position. When everything is running normal doing that you'll know at a glance things are OK without needing to read.
Looking at the pictures, I see a daily driver with 196K on the clock. I'm putting $20 on RED=RUSTY FRAME. Just remember [if it's to good to be true it probably isn't]
Since you are a jeep guy you'll know what to look for.