I was poking around down at the local Trade Lot this morning and found a 58 Topper 16 AH serial # for $100. It was tempting but I passed. If it had been A 158 AF serial # I would have snatched it. What's the difference in 158, 58, M48, and 88 Toppers. They basically all look the same. I know some have pads some don't. Thx