Is end sealing necessary when the moisture content is 25%

I would say you do if you want to minimize splitting. The thing you want to do is prevent moisture reduction from occurring too fast or unevenly. It will dry faster at the ends because of the open grain. The wood fibers do not begin to shrink with moisture reduction until the wood reaches a MC of about 28% so your wood has just begun the shrinking process. If not sealed on the ends they will shrink much faster than the rest of the board and since it will occur unevenly splits are likely.

Thanks for the info Bill ;-) I’ll paint ‘em.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence