If the aspect of the LC hit is armored - there is no effect vs the LC - only a Collateral Attack vs vulnerable PRC.
G12.62:
"If AP-type ammo (i.e., AP/APCR/APDS, or any non-Aerial MG, 12.7 or 15mm weapon, or HEAT) was fired, one DP is inflicted if the Final TK DR is ≤ half of the applicable Final TK#; if that DR is > half of, but still ≤, that TK# there is no effect on the LC except possibly via a Collateral Attack vs its Vulnerable PRC; if that DR is a Dud (C7.35) and/or > that TK# there is no effect on the LC or its PRC."