but,,, what is interesting here is that the paperwork is for the 100 anniversary 72 and it clearly states that the they are jigged bone handles, not delrin, so there is another 72 for you to collect, since you seem to have only the delrin ones.

i will take some pics when i have the time and post them here for you to see and to read.
btw, looking at the scales on my knife thru a loupe they also look as if they are jigged bone and if they aren't bone, then they are a very good imitation.
i suppose this needs more investigating

here is the pic.