mixvibes pro and U46DJ?  personally i see it as a waste for pro to work with U46DJ.  I would suggest echo audiofire8, edirol fa-101, NI audiodj 8, or the xxxx(i forgot how to spell it) 16/12w, 
but for your question, you can see it from the firmwire version, if its 1.xxxx, then its the old one. if its 2.xxx, then its the new old. am i bullshitting? yes i am, if you dont purchase the product, how can you install it and check the firmwire. LOL,  
  
  