Timing Chain Noise...

Hi there I'm the owner of a 1994 C180 Classic

For the past few days I've noticed a distinct noise coming from the engine which sounds like the 'Timing Chain' because the noise is constant and present at idle and increases in velocity when the engine is revved.

I've now been to a few mechanics who have advised me to replace most of the components of that system including: Timing Chain, Tensioner, Guard Rails etc...
This will end up to be quite costly...

I want to know if this is really necessary to replace all these components or just the Timing Chain?

Thanks