Originally Posted by
madpogue
Looks like a sort of false bi-plane. You can see an upper and lower horizontal section, but it appears solid in between.
And 12/1984 would be a 1985 model.
It looks like Sierra and High Sierra used the same solid fork in '83. In '84 High Sierra switched to a bi-plane fork, and then unicrown thereafter. While Sierra kept the same '83 style fork to '85 if G1284 is the 1985 model. Akisu forks.