My 84 is total glass. I an in the process of fixing the trigger bar spring. My 88 is now mostly glass like, but the last 1/4 has a bit of binding - and I just have a feeling this is where the frame contacts the disconnector. I may WAIT to get this when I detail strip to get this gun cerakoted. I was able to get a carbide stone in there with the hammer cocked and the slide off to poilsh the forward portion on the frame - but of course I cannot get to the rear portion and complete the job will I detail strip again. (I'd go in and do it now, but I get a tad nervous about putting the safety IN AND OUT.
IF you look at the close up of Smecky's pic of the disco and trigger bar interface he states that THAT is the place of the largest amount of grit. I just cannot see exactly which interfaces hs is referring to.