Well Steve!!
very obviously, dealer undercoating (if purchased) was installed by the dealer after delivery (and usually after sale, as that was a dealer option they tried to sell to the buyer!).. so based on JohnZ's post, and what we know about rear wheel well factory undercoating (installed by Fisher), NONE of that should be found on exhaust or suspension parts... We know you knew that!
the thing about 'dealer undercoating' is that there were no standards... every dealer likely did it differently, but we do know that all the parts were installed when the dealer did it. Some dealers even used a 'shop down the street' for applying it. Sometimes dealer undercoating was even applied to the underside of the hood (come see my '57 sedan!)..
VERY head undercoating everywhere underneath and even under the hood, to the point that the hood is MUCH heavier... surprised the springs hold it up!
