Like AcE said
Both screenshots are clean.
First 1 is Speccing someone while respawning (If you press enter you can see 1st & 3rd person vieuw)
First ScreenShot:
The first screenshot is clean Obviously.
it's not 3rd person hack. Most 3rd person hacks have a Crosshair.
How Do You Reconize?
How did i reconize.. well first of what AcE said he's speccing or waiting to respawn.
The possition of the Shotgun on the screenshot says enough. 3rd players aim higher.
Info
If play in a 1st person server you always can spec someone durring the game in 3rd person vieuw.
That's how screenshots are looking like 3rdperson vieuw.
A First person player Aims more to the spot where the ''3rd hacker'' is aiming.
A Third person player Aims Higher & Aims more with like 3Cm of the top of the gun in the same line of the gun.
Easy to detect 3rdplayes. but alot of 3rd players are also using Walhacks with WALLS REMOVED (Nop didn't see it much. but only on the floor there are like little walls you just can see trough the whole map.