Yellow paint inside my M&P 9

[Bluez]

At first I thought it was rust ( shot in a very light rain yesterday) but gun was almost packed up by the time it started raining.
And besides modern handgun like this should not rust.

On closer examination via camera it appears to be yellow paint.
Weird.

 

[SilvrSRT10]

Smith must paint some of them yellow for some reason. Maybe as a parts identifier. Here's another picture showing the same part with the same paint on it.

 

[SilvrSRT10]

I think I figured it out. It's to "highlight" the sear deactivation lever which needs to be pushed down during gun breakdown and cleaning. The M&P can be broken down just like a Glock but some people may not be comfortable with pulling the trigger in order to do so. M&P had the sear deactivation lever so the gun can be broken down without having to pull the trigger.
[ame]http://www.youtube.com/watch?v=s4Hd3R88nF0[/ame]

 

[Bluez]

Aha!.. I understand its some option based on some screw setting.
Dont remember that level from my earlier MP9 (this one even though a gen1 is 2017 production)

Was kinda unsettling at first made me think it might be rusty..

I leave it in the setting were you pull the trigger.
I double check the chamber every time before I do..