Congat's on your purchase!!!  According to the listings in Crestline's Oliver Hart Parr book, your machine is a 1929 model. The production for that year is 43849 to 46343.  Hope all that was missing was the belts, did you get the wrenches and extra concaves with it? Regardless, enjoy it, as I enjoy it's 'baby brother'   (22X36) serial 52256 (yr.1942)
                                                              Murray