Top mp40 value as of 2015?

I own a TOP mp40 that I only ever shot a few times. I have everything that came w/ it and the box; unfortunately the guy who sold it to me mailed the mp40 in its orig. box and stuck the postage labels on the box and basically ruined it, in my opinion.  I can not find much info on these wonderful mp40s in the USA, for whatever reason (or prices). I was thinking about parting w/ it since I just acquired a MGC M76 mint in the box. As you may know the TOP version is very heavy and well made; it looks good in person but the prices are HTF on the net. Any ideas of value?  -Thanks!