Unless the CARC's finish is so rough that it actually has protruding bumps or extremely thick texture, I wouldn't think that decals won't stick. Vinyl decals should stick pretty well.
In any event, prepping with alcohol is a good idea. I would also suggest spraying some very soapy water onto the surface before applying the decal. This allows you to adjust it without worrying about having to get it perfect in one go. For large decals, remember to have something you can use as a squeegee, like one of those Bondo spatulas sold at Walmart. Use that to force water out toward the edges once you get it perfectly centered. You also eliminate air bubbles, because those same bubbles are now just filled with water and will be forced out with your squeegee.
Just gently set the decal down onto the soapy wet surface, and carefully, slowly use the squeegee to force the water out, starting from the center working your way out.
