Tom,
The easiest way to get them back in is as follows:
1. Set the casing on its side so that the cells will be horizontal. These cell perform best when the electrolyte has to wick only up 7 or 8 inches as opposed to nearly 2 feet.
2. Remove the regulating valve at the top of the cell. To achieve this first remove the small disc like cap at the top of the valve then use a bird beak pliers to insert into holes of valve and turn to remove the valve. Once a cell casing is fully intact some pressure should be released if none isn't it means that there is a leak some where and pressure is not being allowed to build.
3. Use generous amounts of CRC or WD40 so that the cells could slide in place. Once the cells are in place reinsert the valve at the top of the cell.
When you confirm that code I will be able to tell you when and where that cell was manufactured so you can know the true age of your battery.
Good Luck
P.S.
About the CRC, don't put in on before you lift the cell as it will be quite difficult to impossible to handle. Lift cell horizontally and offer it up to the opening allowing enough of the bottom of the cell to enter the casing so that it could support itself (stick out horizontally binded between another cell and the casing wall) then spray CRC all around on all four sides and then give it a good horizontal push (you may or may not need a friend to assist dependent on the resistance you get) to get them back into their orginal position.
Oh... one more thing it doesn't matter which terminal is up or down up sit down and arrange them (on paper first) the easiest way so that you could link terminals together to get you desired voltage and beginning and end terminal in the desired location.

Cheers....
Damani