Fascism isn't necessarily a clear lineage of the ideology itself but it can be mostly neatly summarized as a rejection of the enlightenment and an attempt to get rid of the ills of society through culture. Pol pot in this case actually neatly fits into both characteristics with a full hearted rejection of revolutionary theory and adoption of counter revolutionary theory, as well as the attempt to fix the ills of society through culture itself.

A lot of the original fascists had links to elements of nihilist and anarchist theorists due to the overlapping philosophical-ideological criteria to create the conditions for the idiosyncratic and in most ways contradictory principles of fascism. Pol pot probably qualifies along similar lines as these early fascists with his initial identification with communism and subsequent counterrevolutionary turn