All 9500's left the factory with "Beocenter 9500" written on the left rear flap. 9300's had a blank flap with not even a space for the writing.
It is possible that the flap could have been replaced, as the only one available form spares stock is that from the 9300.
In my experience this does happen as I have replaced several myself. In fact I have a 9500 advertised now with blank flap AND no white stripe!!
This particular one is the second one I have seen "sans" white stripe although I do believe that Lee has had one in the past. This could be due to shortages in the factory during manufacture.
The easiest way to check whether 9300 or 9500 is to look under the flap. 9500 will have separate phono input whereas 9300 has combined Phono/Tape2