Actually this bite of reality ought to show some of the C20 worshiper's here that there is more than one way to remove the skin of honorable feline.
Where's Waldo manufacturing philosophy makes trying to outguess actual "current" battery construction risky. I'll bet that is not a 5% antimonial battery. Probably 2.75% and knowing Us Battery, they may have adopted the hybrid stance and use calcium in the negative plates. This raises the voltage profile substantially. But not of course as much as with a calcium/calcium battery.