Only runs 40 Degrees advanced

Seems like I read somewhere that not all aftermarket distributors are indexed like a factory distributor is. So maybe with the pump drive gear slot pointed at the first left intake bolt and the engine is at tdc, the rotor points at no 1 tower on the cap with the stock distributor.
Say you pulled the stock distributor out without turning the motor and put your aftermarket distributor in and due to the shaft being indexed differently the rotor now points to no 8 on the tower and you have to make no 8 now no 1. Is the distributor you replaced the broken with a different brand and also not a factory one?