The honda750expert listing you have there isn't right.
The K2 came in a Candy Brown Metallic (sometimes called Forest Brown Metallic and at least 2 other names), Candy Red, and Candy Gold first with gold tank stripes and later with black tank stripes. The K1 went thru the similar stripe colors on its gold tanks, with gold stripes, then black stripes, then black stripes with white inserts (New Factory paint job).
The Brier Brown (note the correct spelling here) first appeared in the K3 model. It is a lighter brown with no 'depth' to it.
The 2 'browns' are different: the first one is Forest Green Metallic sprayed over Candy Red. The Brier Brown is opposite, sometimes with and sometimes without the metallic in the top coat. They were said (by Honda's rep at the time) to be "recovery" colors on tanks with bad paint jobs: if a Candy Red went bad they sprayed the metallic Forest Green over it to get the K2 version, and the latter version was opposite, appearing until the early K4 series bikes. Then the tanks (vendor) changed and the shape with it, having a different petcock (with a spigot) altogther. These later tanks correspond to the flat-top seat, too.
My K2's green color wore off the brown during a 6500+ mile, 2-week-long tour in 1975 with a [heavy] tank bag aboard. The Green showed thru where the Red wore away. In 1979 I had it repainted to gold epoxy so it wouldn't wear away again. It still looks good!
The K2 also came in Candy Gold before about 3/72 production, after that it was Candy Gold Flake with very fine flakes - which became a K3 color. It also was available in Candy Red (as leftover tanks from K1 production, same tank). Honda wasn't hard-and-fast about the colors of the bikes like today's "history buffs" seem to think: it was pretty mixed through the whole run.