Takumar knobs and levers?

I have noticed that certain Takumar M42 lenses have additional bits and pieces on the mount end. I know what the little silvery 'auto' pin is for - most of them have this. However, some have a robust looking lever sticking out that is similar to the iris actuator on the M and A series (and upwards) lenses. There is also a solid looking, square block of metal about 5mm x 5mm on the edge of the screw threaded m42 flange.

What are these for please and will such appendages foul anything if used in a modern DSLR?
Also, if the lever is a secondary device to control the iris, is the Auto Manual switch rendered inoperative?

I assume you are using the M42 Takumars mounted on a thread-to-bayonet adapter ring. If so then none of the bits and pieces on the rear of the lens do anything at all, nor will they foul anything on the camera body - with ONE exception. You should set the rear slider to manual - that is, the letters 'MAN' should be visible before mounting the lens. You may have to hold the tiny outer pin in with a screwdriver or similar before you can move the slider. Forget to do this and the the lens can jam in the adapter.

The lever you mention will be found on some SMC Takumar lenses and is for open aperture metering on the Spotmatic F. In other words, like all modern SLRs the metering is carried out with the lens wide open. With earlier Spotmatic cameras, turning on the meter closed down the aperture to the working value, thus darkening the viewfinder image at the same time.

Thank you both. Having had a lens jam in the camera (one with a Richo pin that I failed to notice) I wasn't happy to experiment with something else having extra appendages on its rear end.