look used to make p15 and p18 bindings, those were the same as the fks 155/185. Look also made p10/12/14s, those both have pivot heels also, but they are a different design than the fks. Rossi's versions or the p10/12/14 series were call the power series, hence power100/120/140s.
and yes, px refers to the modern fixed heel look bindings. Axial2s are the same thing as the px series.