this is what i got from Skuzzy:
Do not be fooled by the name.  It was not uncommon for planes in the 
same squadron and flight groups to have radically different paint 
schemes.
Right now, I am not aware of any duplicate skins in the P51 listings.
----- Original Message ----- From: "Mus51" 
To: "Roy Neese" 
Sent: Monday, November 19, 2007 5:21 PM
Subject: Re: 55FG/343FS P51 skin
Hey, I found that out myself but for some reason i think we could change
a few of the duplicate skins we have (2 357th and 2 2ACG 's) if possible
Thanks for the time looking into tho Mus51
  ----- Original Message -----
  From: "Roy Neese"
  To: "Mus51"
  Subject: Re: 55FG/343FS P51 skin
  Date: Mon, 19 Nov 2007 12:31:22 -0600
  P51 skins are all full right now, but I do manage to swap in a skin
  occasionally when no squads are using them.
  ----- Original Message ----- 
  From: "Mus51"
  To:"Roy Neese"
  Sent: Sunday, November 18, 2007 2:57 PM
  Subject: 55FG/343FS P51 skin
  Hi there, I finished a new P51 skin and i hope it can be put in the
  game
  sometime. With kindest regards Mus51