This helmet is team issued. It definitely looks game used. There are so few photos other than Jim Plunkett from back then to even try to photo match, but all the characteristics of this helmet say its team issued and possibly game used.

You may want to do your own homework to verify exactly what the background is

I do feel confident in saying that it is team issued by photo matching other helmets that are similar to this and have all the characteristics or at least most of them

Item in the picture is the item you will receive