HPDUS was browns? I read that code as doubleshot keys, PS2, black, 120 keys, US layout? If you have one, then you are wiser, mind. A bloke something69? was selling one a while back, mentioned busted keys and asserted it was browns - so I am quite likely wrong.
Ugh cherry crazy.
Anyway, I think LPDUS means:
L = Lasered (cherry's site confirms this board is lasered)
P = black keyswitches, since P,Q,S replaces A,E,F= black,brown,blue for PS2 vs usb...
D = 120? blind guess - but
http://geekhack.org/showwiki.php?title=Dating+Cherry+keyboards doesn't have a code fer 120...
US = United States layout.
I don' have access to a mess of blue or red keyswitches - else I'd stuff them into something and be happy.