if the cluster is anything like my 91's, probably a pain.
would be something like this... (don't quote, just a guess on whats involved)
take out cluster
disassemble cluster - even removing LCD panels from cluster
carefully peeling/removing the green film from said THIN glass LCD panels
applying different color in some manner that is appropriate (adhesive or something)
reassembly
praying it works....
Those lcd panels are VERY thin and delicate (at least on the 91).