RS= Red Seal DB= Date Back PB = Plain Back They are different types of Nationals from different years. As for the signatures some are hand signed, some are stamped, there is even purple ink that some are stamped with.
Is there anyway to tell a hand signed from a stamp? Also, I assume this note is a 1902PB...is that correct?
Yes, the date back will have dates to the right and left of lady liberty on the back. I would guess that the note posted has stamped signatures but I am not an expert in that area.