Ken,
The wheel assemblies on the RV-12 are manufactured by Matco and Section 4 of the builder instructions shows the following part numbers.
Nose wheel assembly is part number WHLNW51CC G25
The main wheel/brake assemblies are part number MHMHE51B
If you go to the Matco Mfg website they have parts lists available for the individual parts that make up each of the wheel assemblies.
Hope that is what you were looking for.
Happy flying,