Distinguish between AW5 and 6 in script

I'm trying to create an application in Automator to automate the conversion of AW to iWork. I'm using one of Yvan's scripts to convert AW6 to iWork successfully. The only step remaining is to convert to AW6 from 5, something that shouldn't be too hard since all it has to do is open and save. However, I can't find a good way to distinguish between AW5 and 6. In his script, I believe Yvan does this here:

on AWtoAW6(leCheminOriginal_UniText) -- leCheminOriginal_UniText est Unicode text

local leFichier, flag, nf, l, nouveauChemin

set leFichier to leCheminOriginal_UniText as alias

try

tell application "AppleWorks 6.2.9"

activate

openleFichier

set nf to name of document 1

if nf contains v6 then

set AppleScript's text item delimiters to v6

set l to text items of nf

set AppleScript's text item delimiters to ""

set nf to l as text

end if

if nf does not end with ".cwk" then set nf to nf & ".cwk"

set nouveauChemin to cheminDeStockage & nf

tell application "System Events"

if exists (file nouveauChemin) then set name of file nouveauChemin to (text 1 thru -(2 + (length of "cwk")) of nf) & my horoDateur(modification date of file nouveauChemin) & ".cwk" (* name stamped *)

makenewfileat end of foldercheminDeStockagewith properties {name:nf, file creator:"BOBO", file type:fileType}

end tell

set leFichier to nouveauChemin as alias

savedocument 1 inleFichier

closedocument 1

end tell -- AppleWorks 6

on error

set rapport to rapport & msg96 & nouveauChemin & return

end try

end AWtoAW6

But I'm not sure. What I need is a script that opens, checks if it's an AW5 file, if it is opens and saves in AW6, and then proceeds to open my other script that can do the