This is very unintentionally an indictment of whatever education system you come from... But I'll give you a straight answer.

The freikorps were organised to eliminate communist rebellion. Their roots are anti-communism. The roots of fascism are anti-communism. The only shared trait that is true in all forms of fascism is that it is a violent reaction to communism. Everywhere in the world that you look, Spanish fascism, Italian fascism, German fascism, Chilean fascism, etc etc etc - All forms of fascism are different, but the one shared trait they all hold is that they become funded and grow as a violent opposition to communism. Fascism becomes funded and endorsed by the capitalists when they need to destroy a communist threat to capitalism. This is evidenced even more by the fact that fascism never becomes anything unique when it wins, it isn't special or different to regular capitalism, when it wins and destroys the left like it did in Spain or Chile it just slowly turned itself back into liberalism, neither were overthrown. Fascism in those places simply no longer had a reason to exist after it had defeated the threats to capitalism. Fascism is the capitalist state turning to ultra-violence in order to eliminate any anti-capitalist threat that exists to it, in most cases this is communists.

There is a reason that the poem goes "First they came for the communists", there is a reason we are their first and greatest priority.

With this understanding you should now realise that the freikorps were absolutely a precursor to the nazis.