fork clamp question

I have a few top clamps and a few triple clamps. The fork tube holes line up but the center spindle does not. Is there a different offset somewhere in the years?

Yes, there were different offsets for solo and sidecar triple trees, both 7" width yokes (1954-63) and 7-3/8" width yokes (1964-71) came in two versions. Triple trees for sidecar use bore the casting mark "Sidecar" (7") or S/C (7-3/8"). Offset is smaller for these than for solo riding triple trees.
From 1972 on, NV kept the 7-3/8" width but increased offset for solo riding.

- Knut

That explains it...I hope. We struggled with this for a long time and how he got 6 pieces incompatible with each other is a mystery. Thanks.