Sorry, I meant the coat to say early 20's and not 30's.
Nice coat! I have one by the same Ning tailors just like it, but without the unique Philippine insignia "slots" in the collar.
These slots are apparently only seen on Philippine made uniforms of the late teens and early 20's. I have a couple examples of insignia with this butterfly type folding attachment. They were used not just by the Army, but on Philippine Constabulary uniforms as well. These type of insignia are very rare and I assure you that you will probably never find a complete set for the collars of your coat. Of course when officers rotated back to the states, they still wore these uniforms with the common pin back insignia of their new unit, so you can use those as well. I have a white dress high collar coat that had the slots carefully stitched closed and the new insignia pinned over them.
So anyway, your coat is most likely early 1930's and could be used with the bronze buttons and insignia or the gilt insignia as worn from 1924 to 27. The buttons of course will need the small, usually brass at this time, split rings for attachment.