Magnet in, or magnet out usually makes no difference acoustically. It is a style or cosmetic thing for the most part. Some nutty purists will build two boxes, one with magnet in, and the other with magnet out. The theory behind this is that there are non-linear distortions present with normal transducers, and using one each way will concel those non-linearities out.
DB- A single-reflex bandpass is one where you have the woofer totally inside between two enclosures. One enclosure is sealed, the other is vented. the only thing getting sound into the listening area is the port.
If you can touch the woofer, front side or back side without reaching through a tube, it is not a bandpass.