Originally Posted by Mark Albery
The factory can confirm if you supply either the kit serial number or the spar serial number (etched on the spar). Spar serial numbers greater than 8-869 are -1 .
One caveat with basing it off the Builder's Number (aka: Kit Serial Number). Example: I purchased my current RV-8, and it has a low Builder's Number, one which is prior to the "Dash 1" wing availability. The original builder/owner bought the empennage kit years ago, and the Builder's Numbers are assigned with the empennage kit. He didn't buy any other sub-kits at the time. He built most of the empennage when he first bought the empennage kit, but stopped building after that.
Fast forward to a few years ago when he decided to finish the RV-8. He didn't like most of his early workmanship, but kept the rudder and ordered new fin, stab and elevator parts. He then bought a new QB fuselage and QB wings from Van's (with the "Dash 1" wing). The rudder is virtually the only component from the original kit on the airplane. So although the airplane is new, with a "Dash 1" wing, the original Builders Number is an early one and would not indicate that the airplane has the "Dash 1" wing.
With people mixing and matching kit components of various ages, I'd rely on the spar serial numbers for confirmation.
But remember, there is absolutely nothing wrong with the original, non-"Dash 1" wing.