Some parts yes, others no. It's strange how the parts are priced. Take the front hubs; Kyosho $10, OFNA $14 both are very similar cast alloy. Now buy the steering pins and the bushings, $8 for two shoulder screws and two flanged bushings.
However most of the parts are about the same price as Mugen and others and since they don't break so much the cost of parts is moot.