Those weights were added to balance the converter, nothing to do with engine balance...... I'll guess as long as only a small amount was removed you'll be OK...
Is the weight "flush" with the housing, or protruding or extended up? If so, maybe it could be lightly hammered down. Be careful not to damage or distort the housing!!!
Ended up putting a new converter in it from a converter shop that rebuilt one from a core he had , the first one made noise while the engine was running , the new one is very smooth