How to swap features, but not file names?

I am using SW2010 with SP4.

One of our junior guys made a copy of a library part with the intent of modifying it into a new part - Something we do regularly. I reminded him to use the "save as copy" check box. All is well. Until I realized that after a successful copy he made the edits to the original. Not a big deal if the original wasn't already used in who knows how many places.

So I need some thoughts on how to swap things around. One option is to manually fix things back to how they should be (feasible, just not preferable).

To clarify:

Part O (original) has features A, B, C, and D. Part O is used in several existing designs. I have not used SW Explorer to quantify the extent of its use.

Part O was opened and with the Save As function and Save As Copy selected a new part file was created named Part C (Copy).

Part C was to have features A, B, C, and D modified into features W, X, Y, Z.

But instead Part O had its features modified so it now represents what Part C should be and visa versa.

If I perform a SW rename the references to Part O will be notified of the change and keep their link to the that part regardless of the name given.

Can I just perform a Window Explorer rename to set the files right or is there an internal ID that will cause headaches?

Clear as a politician's promise, right?

Thanks, Daen

SolidworksParts And Features