Spotless ?

[Kahrnut]

Is there not something missing on the rear of the slide?

That's the spot (-less)

 

[jeep78]

Is there not something missing on the rear of the slide?

The left handed safety lever, must be optional on his gun.

 

[mfoster]

Spotless could mean in certain spots.

 

[aFarewellToKings]

If you don't look so closely, you will spot less.