The current general trend in today's antique market is to leave pieces in "as found" condition, not counting the work needed to prevent further damage.  In the past, many locks were converted back to flintlock in an effort to increase their value.  Most lock reconversions I've seen have been poorly executed, and a quality original percussion conversion can be more valuable in today's market than an amateur flintlock reconversion.

This lock had an attempted reconversion to flintlock, with a missing pan and no other exterior parts.  I removed the prior lock work, and then installed a complete set of exterior parts.  Once assembled, I applied layers of new patina to bring the color and finish as close to original as possible.