I have mounted a Walz branded screw-in hood, it accepts filters but isn't perfect as you can see.

The images show some dust, yes, but the earlier image posted more accurately shows the "cleaning marks"/"faint scratches"/whatever other terms you would use to describe an imperfect front element.

I'll make a point of shooting a roll ASAP with it to show any effects and find whether it is accurately focusing on a non-FSU body.