I have this code within my add-in, because of version differences:
If Val(Application.Version) < 10 Then
Application.CalculateFull
Else
Application.CalculateFullRebuild
End If
You could probably use something similar. As far as I know:
< 8 then Excel 95 or earlier
= 8 then Excel 97
= 9 then Excel 2000
= 10 then Excel 2002 or XP
= 11 then Excel 2003
= 12 then Excel 2007