Well, the 901075 does not sound like any Patek movement I've heard of, a serial# I would say.
Usually, the ranfft movement database is a good place to start for identification. However, they seem to have very few Pateks listed, the closest one I see is the 10-200 which is a more typical style of calibre# for Patek wrist watch movements (the movement diameter in lignes is the 1st component of that calibre# by the way). You can see it here:http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Patek-Philippe_10-200
Looking at yours, it would seem to be a rather early wrist-watch movement from Patek, likely 1940s rather than the 1950s shown in that link above. I see no evidence of shock-protection on the balance and also no fine-adjuster there either. It also has the American import codes on the balance cock, which may also help in identifying/dating it.
Some Patek movements do have the calibre# stamped on a plate under or nearby the balance wheel, did you try looking there? An example (23-300 ) is shown here:http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Patek-Philippe_23-300PM