[ainarssems]

If there was anything wrong with the shock I would still be tempted to replace both sides.

That being said the fault has not been diagnosed and I would not be throwing huge amounts of money at the problem replacing parts and hoping that it will cure the it. I don't think you get many issues with struts other than air leaks either bag, o-rings or residual pressure valves all of which could be replaced for a lot less money than whole strut.

For all we know it could be lost nut, screw or socket rolling around somewhere making the noise. If it was me I would leave it alone and live with it after verifying that it is not something that affects safety.