PSO-1 Scope cannot mount to the AK74,
The scope mounts on all the AK weapons are the same, the scope can mount to the Ak101 and the AKM but not the AK-74.

The gun models all have the same side fitted scope mount so it would be odd if the Ak-74 is unable to

and I am not referring to the AK74SU as the model does not have the scope mounts.

Developers picture for Ref is attached {F31582}