The only Austin and Halleck lock I have worked on was covered in a gritty coating, inside and out. IMHO, the coating covered allot of minor casting imperfections in the lock parts, especially the internals.
Even the springs were finished with the same coating.
IMHO, once the the frizzen was re-hardened and the coating removed from all moving parts, including the inside of the lockplate, frizzen spring, and foot of the frizzen and those parts polished, it didn't seem too bad.
The lock isn't the quality of a Chambers, by any stretch of the imagination, but it wasn't too bad, for a Spanish made lock.
God bless