which model vpi sds do I own?

I recently purchased a used vpi sds.The one that i received is 16x3.5x8 ins. in size and the faceplate of the unit is practicly flush with the sides of the unit.The ones that I have recently seen for sale is 19x3x12 in size and the faceplate extends past the unit on the sides.I would like to know if I have an older or newer model and is there any sonic differences or benefits in owning either one.[note] I have not audition the sds yet.