first, sucks about your space bar.
second, try looking up "plume or mold" threads, there are tons of them with pics galore.
third, if it is tan, i think cheifstrongleaf may be spot on with water spots. natural discoloration (possibly even minor damage) to the leaf done during curing and rolling that will not affect the flavor or burn at all. if this was a core fuente (green at the base of the band) they are not as stringent on quality controll of the leaf as far as appearance at that level; it might be ok for an 858 maduro, but not acceptable for a higher line, like a hemmingway maduro or anejo.
smoke it and let us know!