Top and bottom pairs are directly connected, i.e. four plates are zero ohms between them.
Middle plates are directly connected to each other.
There should be no conductivity between the top and bottom pairs to the middle pair.
Those are the two connectors at the top, i.e. one connector goes to four plates and the other goes to the middle two.
As long as they are electrically connected to the top with no resistance, and they're clean, they should work
. It's just copper plate as far as I can tell.
I have stored mine for several years off season with fresh water