If the extra holes + the original 36 added up to 40 per hub, we might assume these were left over from the Tandems. But I believe I count an extra 18 holes per hub, per side! This would give a spoke count of 72 for the entire wheel!

Any opinions on whether this weakens the edge of the flange of the hub? It certainly looks as if it would to me. Interesting that we have both a front and a rear example.