when you turn it on it should say "128 mb RAM" or something along those lines
or you can just open it up and see the chip.
i dont think theres anyway to know if it has the pad upgrade besides actually opening it up.
when testing look out for:
-pad response
-all the outs give sound
-the in's are able to receive sound
-usb is functional
-midi ports functional
-sliders function (mine didn't, easy fix)
-buttons function
-and just be on the look out for any cosmetic damage (could save you some money)
-and many other things i can't remember at the moment
just play around with the thing really.
myspace.com/1018pm