Loose pin on front brake calipers

I was thinking about painting the calipers ... and noticed a pin on both front calipers was sticking out. I pushed it in and there was no resistance and it went all the way in, it did not click or anything. is this per design? the rear calipers don't have the pins.

@boardude has a nice post re painting and has some pictures (third picture, the bottom pin where the red paint ends)
its the pin just above the boobs lol

https://www.tundras.com/threads/painted-calipers.3023/#post-44882

edit:
in pic 4 and 5 you see 2 similar pins above & below the boobs.
I could only see the top ones maybe because the way I was parked.
both top ones were sticking out. mine is a 2016 and OEM brakes.

 

Those pins are held in by a spring loaded clip on the back side. A new one usually comes with the pads when you swap those out. I would check to make sure that pin is still in there.

 

It is normal that the pins will slide in and out maybe 1/8 inch. Look at the inner side of the calipers and you should see the wire spring that retains them.

 

I'd go as far as to say this loose pins are a good thing.

Up here in the salt belt the pins freeze in place and can't be removed. Off to the parts store for a complete caliper

 

Thank you guys.
Main reason for thinking about painting was to prevent rust.
One of my older car had no rust on the OEM calipers after 4 or 5 years and it looked like the same caliper material as Tundra. Took it to Les Schwab for brake work and their "new" calipers rusted pretty bad in less than 6 months. They said they have to put new calipers and it's part of their brake work... No other option and I was very busy at work ...
after that and couple other les Schwab mishaps i decided to stay away from Les Schwab.
I have a feeling oem Toyota calipers are like like my other car and won't rust so maybe I skip the painting for now ...
in 2 years i don't see any rust on them, will see!