Lucille,
On my '41 ton and a half, the battery tray has two pieces of wood, about 2 inches by 6 inches, 1/4" thick, that sit on either side of the battery, between it and the side of the tray. Each one has two, dime-sized holes in it, corresponding with the rivet heads on the inside (battery-side) of the tray. I'm guessing these are to help keep the battery snug? Gives a very definite size to the battery.
Maybe they're not original, but sure seem to be. . .
-Michael
