I looked on JC Whitney, no luck.
They are a square piece of steel wide enough to fill the space between the legs of the U the shock goes into. This piece is long enough to reach back to the rear of the swing arm. There is a bolt that holds a block in the rear of the swing arm. This bolt gets removed and a longer bolt goes down through the steel piece in the shock mount.
Their are two pieces of steel strap welded to the square piece back just before the bolt. They are high enough to have holes in them to bolt the shock into. This moves the shock toward the rear, lowering the bike.
Making a set should not be too hard.
Leo