Both machines are exactly the same machine in terms of internals and actual machine.
Yours comes with the 6 inch backing plate and the counterweight for 6 inch components that's all.
I have your model and I didn't even bother replacing the counterweight for the smaller backing plate (5 inch) but if you want to, quite a few online shops offer the smaller counterweight.
Anyway, don't return it.
-John C.