A factory new RCM for our cars ( if there is such a thing anymore ) will be just like the one that came in your car when it was new.
Over the years and heat/cool cycles under the hood, along with mechanical stress, the wave soldered factory boards
will most likely develop the cold/cracked solder joints.
I am of the mind that a 'repaired' one , done properly, is probably MORE reliable than a factory issue one, since it has extra solder on the critical joints.
And then, I could always be wrong.