Gordon, I think most of the changes were "internal". I can tell the difference by looking, but can't really tell you what to look for off the top of my head. I think (I use this loosely) that you can tell by looking at the wing spars. If it has normal "blade" style, it is a 1st or 2nd Gen. I think the 3rd Gen. utilized spars that looked more like a "T". But as I said, I may not be exactly right; it has been awhile since I've dealt with the Viper Jet.


George