I do alot of wood working with barn wood, sometimes when I dont have the pieces I need i have to improvise with newer dimensional lumber. Wire wheels add texture as they remove the softer wood and the harder layers of the grain protrude, just like finish sanding go with the grain. A quick surface burn with a weed torch and then wire wheel also make some great results. Ive beat boards with hammers,wrenches,chain, and even drug a newly constructed table top that had been painted down our gravel driveway with outstanding results after sanding and stain/glaze/danish oil. Grey stains, dark stains, and use of glazes oan or paints normally can get you really close. Its really hard to recreate mother nature’s beauty.

Finish the first shelf the same way you do the new shelf and they will match perfectly, by that I mean wire wheel and grey stain with some darker grey/brown glaze. The problem with matching natural grey faded wood that’s unfinished is that the exterior is dry and looks dry and dull, any stains or techniques will not give you that dry soft finish mother nature does.

Iron sulfate like applied to lawns to give it color. When I sprayed lawns in college it was a big deal if we got spray on wood fences. It'll turn it a nice grey color.

Thanks for the tip KB64!!!