Lawn & Garden -- NOT!!!
Well, it took a bit, but I finally got a battery that doesn't say KMart Lawn & Garden. It's a GS (who bought out Yuasa) Here's pictures of the battery, and of the box.
1) the battery post do need some minor filing to properly fit the original battery clamps.
2) The original cover, an S600 specific part, has to be modified since the posts are about 3mm taller than the original,
3) Note that the posts are swapped front to back.
The pictures show the correct part number for the GS battery. DO NOT get the battery with the (S) as that indicates a "standard" size battery post, not the smaller one you need.