This has always been a major discussion with log siding. Some say that it helps stop warping. It really doesn’t matter in my book, but you DO need to make sure that the wood is perfectly dry before staining even though it is kiln dried. Wood can gain moisture content after coming out of the kiln so you will want to stack with separating sticks and covered on top only, not sides, to allow to finishing drying. If stain is applied before completely dried the siding can start resin bleed where sap runs out of the knots for years and cannot be stopped.