Winchester switched the color of their primers in the early 2000s, IIRC. Initially they were billed as being more sensitive. At the same time they switched the packaging of component primers from white to blue boxes. The first lots of the blue packages had a little white triangle in one of the upper corner touting the new, improved sensitivity. I burned through a few cases of them.

Winchester also used to use both paper/cardboard inserts as well as plastic/styrofoam. Even on some of their premium handgun ammo. I've had boxes of .357 Silvertips with the actual cartridges held in cardbard "trays" made of similar paper to the outside box.

HCM has already commented on the primer sealant.

Knowing the specific vintage will probably help narrow things down.