Colt HBAR II Appendix A or B or??

[Rumblemonkey]

Hello, helping a friend to legally configure his older Colt AR-15 HBAR II so no RAW needed. Can the HBAR II be made compliant, or is it completely undoable in Appendix A of the algorithm (Violates PC 30510A). I used the search forum-no luck! I heard from "a guy at Turners" (I know!) that is can be made featureless, or disassembled to comply. THANKS!

[Quiet]

How is the receiver marked?
^Need to know the exact markings.