The base gun is a Norinco 1911-A1

First what is a SEAR, and what does it do, and where is it located.
The most common thing I see donr is trigger, hammer, and sear.  Do these require smithing to fit?
Also thinking of replacing the slide lock/catch, and installing and extended safety.
Is anything more than a dremel tool required?
how often do the parts fit without fitting or modifications?
Would you advise for or against a guide rod?
 

bump

Absolutely get a guide rod! How else will the spring lock up on the barrel??????