Well, it depends.

Most car mfgs are going to pretty thin rotors- this improves performance (unsprung weight) and makes it easier to service (just replace, no need for skilled machining)...

You need to measure the thickness and see if- after machining- it will still be over the minimum spec. My recollection is that the wear limit on the rotor is only a few mm...so odds are you will not be able to.

Just think of all the money you are saving by DIY...drop 2-300 on new rotors from any vendor and replace them. BMW OE is fine as are the centric ones... rotors are one of those commodities, IMO. Pads I pay more attention to.

GL

A