Yes, there’s limited historical evidence of them using the reverse:

Prior to the Nazis seizing power there was fairly widespread use of the swastika, including in Germany, and its use was less codified so you can probably find pre-Nazi German swastikas being flown that are of the opposite orientation and it would take a real history buff (obviously not a Graham Platner-tier history buff) to be able to tell if that’s a Weimar Republic era warship flying the reverse swastika or if the image was taken a few short years later under Nazi Germany. (Also anyone who can tell the difference immediately who isn’t some dusty old academic in the history department of a university deserves a side eye.)

So yeah. It’s complicated but it seems like it was used, albeit rarely.