Few starting batteries are lead calcium positive plates. About 90% are 1.5 - 2.75% Pb - Sb. With lead dioxide / Ca. These are hybrid units. Various formulas extol various advertising superlatives, but in fact many starting batteries have .035" - .045" positive plate dimension.
So called dual purpose batteries are a cornucopia of varying construction techniques. Most are 2.75% Sb positive, lead dioxide negative with .040" - .050" positive plate thickness. Dual purpose batteries should not contain less than 2.75% Sb. Trojan for many years insisted on not bybridizing their dual purpose batteries and actually used 5% Sb and pure PbO2 negative plates.
AGM battery construction for the most part does not vary widely - except for the Concorde Lifeline. Find an alternative brand BCI 24, 27, or 31 with with .090" positive plates and I'll eat my words. Flooded, VRBLA it makes no difference. Hell, include 8-D 29-plate batteries. They are not going to have .090" plates. Some better brand BCI L-16 flooded batteries have .090" plates. For perspective my 2-volt cells came with .330" positive plates. And 7% Sb plates.
For verification I recommend cutting the lid and extracting modules. Drain the electrolyte, use gauntlet gloves, wool short and splash proof full goggles. My "suit" is 100% wool with a vinyl apron. Cut intercell connectors with a jig saw and inventory was is in the sediment chambers. Staining of the lead dioxide or lead dioxide calcium negative plate is invariably due to antimony migration also called "poisoning". If positive cells are not enveloped, look at the bottom inch of the plates plates inverted, and look for signs of mossing,
Assembly technique and inspection (rejection) play a major role in what comes off the battery line. Pot life of grid paste is absolutely finite, and paste formulation is an art - aside with warring with the front office over cost.
Permutations of materials and construction are endless. A simple .010" plate misalignment can turn the best battery into junk. A screwup in the greening process will trash the best flooded battery.
