So I received the board witht he battery installed and the old battery.
I decided to cut it open to see what the status was.
On the outside, the battery looked fine - the negative side was showing signs of "its time to replace" and the positive side was shiny.
Upon removing the plastic, I found that all 3 coins were leaking:


I play and see my games enough, so I would have caught it in time before anything leaked.
But its difficult to see under the battery, and the plastic can melt and you can have acid drip without even knowing it.
The new ones from Mouser have taller terminals that actually sit on the PCB at a slightly higher height which allows you to see under the battery.
Basically - just keep an eye on your batteries!
So my Ketsui will be working flawlessly, unless I decide to toss 6v at it

