Got sick of waiting for the e-mail
I called direct, and got this (paraphrased) response:
So much of the kits are interchangeable now, that replacing parts "mid-kit", or even after completion is not a problem. He used gear legs as another example (I can't comment, since I'm still on the wings).
Said the engraved numbers on spar/centersection and most all the wing kit parts were just an "extra cautious step" during kit packing/assembly. With the machine precision the parts are manufactured under, they are basically identical from kit to kit. He said they are asking for the center section from your wing kit to be returned, that they will pay for the shipping--have had a few take them up on the offer.
Last comment I found interesting. "If you put the old -8 fuse kit parts next to the new -8 fuse kit parts, except for a very few pieces (center section, firewall, etc) you wouldn't think they were the same airplane. They basically re-designed the entire thing.
Anyway, sounds like they thought it all through pretty well (as usual for Van's), have a plan, and quality/customer safety will continue to be paramount.
Joe