Here is my analysis. Eight of them are relatively easy. The earlier mention of copper lettering on the gold variety is useful throughout.
1. For Cable, Deadpool, Random, Sabretooth, and Wolverine the upper background (maybe left, maybe right) is clearly gold, silver, or other.
2. Archangel has gold fading upward to reddish gold on the upper background for rainbow. The copper foil for the name is distinguishable on the gold variety.
3. For Magneto look at the fold in the background that covers the upper part of M and A. It is clearly gold, blue-green, or silver.
4. For Bishop, see the background immediately to the right of gun.
5. Apocalypse silver is easy: the background for the name, the area just below the name, and just above the head are all silver.
6. Between the gold and rainbow I depend on the gold/copper color of the lettering, especially for "HUNTERS & STALKERS". Copper lettering means the gold variety. Other than that, the gold background on the gold variety looks lighter than that on the rainbow to me.