As far as I understand pyro, the stain should be related to the exposure, so at the development stage silver is reduced and pyrogallol oxidised at a certain ratio and immobilised in the emulsion. So using a after bath the reduced silver will not react in the same way with oxidised pyrogallol.(posted 8816 days ago)I'm using PMK with water stop and tetenal smell free rapid fixer (pH around 6) and do get the stain on Forte 400 straight, which means no after bath is required (stain does not change in 1% Carbonat solution).
Without chemical reaction at the development stage probably no stain.
Regards,
Wolfram