spid help 85 dually

[bns454]

hi im struggling to id the paint code on my truck on the spid it quotes

"55u canyon copper met"
there is also "zyl solid paint"

now after days of going thru every paint decoder I can find on the net I cannot find this colour despite there being heaps of 85/86 trucks this colour on here.
its seems very common but gm don't seem to list it anywhere.

55u comes up as a grey or tan depending on the year and when I search the canyon copper colour I can onley find some listings from the 70s that may or may not match?

(russet 65,canyon copper 62,canyon copper fire mist? 99) ect

has anyone out there decoded this colour or come across this kind of problem before
I have asked this question in the paint section to no avail so thought id try here.
all the images I can find of these trucks seem the same colour as mine some even quote the same code
any help or advice with this would be greatly appreciated thanks