Whith this number of pairs apearing at one time will raise the number of known pairs droping the rarety to at least a 4. $25-$50 a pair depending on condition, will be a 5 if even more pairs turn up. My original aprasal was only looking at one or 2 pair.
From Jeff Laudemans Reno/Tahoe book:
Grade 3 - 5 to 10 pairs known to exist
Grade 4 - 10 to 10 pairs
Grade 5 = 20 to 50 pairs $14-$25

Rarety will go down as more of a particular dice surface.
Value will fluctuate with supply/demand/condition and as the number of collectors increase.