I have been using spitfires for some time so I kinda have a collection of em..Well I decided to clean up all my used bloody/dirty heads from this year and replace the blades for for next season..So I put the heads in some soapy water to set for while..well I forgot about them and a week later I discovered that the tips started to rust a little..nothing new they needed to be touched up anyway...But the rust was on all the heads except one. The other difference in this head is that the ferrule is a slightly different color than the rest..Kinda has a purplish/grey tint..Never thought much of it until now..Not even sure where the head came from as me and my dad have used em for many years...can anyone explain this to me..Did NAP at one point make them with a stainless tip?
I haven't weighted them yet..But ever since we switched to these heads we have used 100gr. So I'm not sure how an odd ball got in...

2nd one from the left

I'd say that's a newer one. The grooves are a new thing.

As companies change suppliers/vendors for their products they very well may change the anodizing process or the materials they use to make them. Chances are the heads were just bought at different times and there's nothing reall that different about them other than the coloration.

If you are really that concerned about it, I would recommend e-mailing them directly through their website. http://www.newarchery.com