I'm no expert but would suggest the cross bolt would be a good idea. I understand that a repaired crack will be okay but then there is a possibility that the adjacent timber may crack over time instead. I guess that you may be concerned about any affect on the rifle's value as a result of installing a cross bolt. If it's done well then I don't think it would make a significant difference.

Either way, I expect there to be a chance of future cracking and the choices would be cross-bolt or another (new) stock.