Quite so, those are possible rectifier arrangements for dual winding transformers.You can wire a +/- supply with only 2 diodes with the disavantage that the ripple will be 50 Hz and there will be a demand for bigger filtercapacitors......And making +/- supply with only one bridge rectifier is no problem, you can use 2 bridges, but that only ad noise and power
However, neither follow the wiring of the posted image, where there is, effectively, only 1 secondary winding in each trafo, because each pair of leads from each trafo is simply paralleled before rectification. ergo: It cannot be either A or B circuits.
Certainly very odd. Why such a poorly specced amp would need two huge transformers is indeed a mystery.
1000uF caps in the PSU... ?
Something like a Pass F5 wouldn't have too many components either and may have two transformers but the rest of the space would have at least a couple of respectable reservoir caps.
Lots of VA, and a low profile case with standard toroidals.
Cheaper (plus fits in the GM philosophy).