PRESERVATION SHOULD ALWAYS BE DONE IF YOU KNOW HOW AND HAVE THE SKILLS OR CAN LEARN THEM. WITHOUT ATTEMPTS AT PRESERVATION EVEN A PRISTINE EXAMPLE WILL BECOME LESS PRISTINE AND A BADLY RUSTED ITEM WILL BECOME MUCH WORSE QUICKLY. NO PRESERVATION EQUALS NEGELECT. ALL IRON OR STEEL ARTEFACTS DUG UP IN ARCHEOLOGICAL DIGS ON LAND AND IN SEA HAVE TO BE STABLEIZED OR THEY WILL BE LOST AND IT DOSEN'T EFFECT THE VALUE.
RESTORE

THAT IS WHERE IT BECOMES MORE DIFFICULT AS SOME WILL ARGUE THAT THE ITEM IS NOW DESTROYED AND OF NO VALUE AS AN EXAMPLE AS IT IS NO LONGER AUTHENTIC. OFTEN THEY WILL NOT BUY IT IF ITS IN VERY BAD SHAPE AND MISSING PARTS AND WILL NOT BUY IT IF IT HAS BEEN MESSED WITH =(CLEANED DOWN TO THE METAL AND PARTS REPLACED AND LOOKING LIKE IT DID WHEN NEW)
MY PERSONEL OPPINION ON THIS IS IF IT HAS NO PROVENANCE AND CAN BE PROPERLY RESTORED FOR A REASONABLE COST THEN DO IT. IF IT HAS PROVENANCE AND IS REMARKABLE BUT IN TERRIBLE SHAPE ,USEING FOR AN EXAMPLE THE SWORD OF SUTTON HOO IT SHOULD BE PRESERVED AS IS AND PERHAPS A GOOD REPLICA MADE TO SHOW WHAT IT LOOKED LIKE NEW (THIS IS WHAT WAS DONE) FOR ANOTHER EXAMPLE THE VENUS OF MILO STATUE ,SHOULD THE MISSING ARMS BE BUT BACK ON THE STATUE IF FOUND

I AM SURE IT WOULD BE ARGUED BOTH WAYS.
FORTUNATELY IF YOU CHOOSE TO RESTORE YOUR ITEM THERE WILL BE NO INTERNATIONAL OUTCRY

SO I WOULD DO WHAT I WISHED WITH IT AS FAR AS RESTORATION AND WOULD CERTIANLY STABELIZE AND PRESERVE IT. OR PERHAPS TRADE OR SELL IT TO A COLLECTOR WHO LIKES HIS SWORDS ROUGH BUT AUTHENTIC

HAVING WALRUS IVORY GRIPS DOES SHOW IT WAS AN ITEM WELL MADE AND EXPENSIVE IN ITS TIME THE IVORY SHOULD ALSO BE STABELIZED AS I AM SURE IT IS DRY AND BRITTLE.( SEE OLD POSTS ON IVORY).