1907 Bayonet Grips - Repair or replace?

[Doco overboard]

Before I change anything I would consider how I would maintain the current grips with the piece. If they were going to be permanently separated and then lost to the bayonet I would leave them with it. However, not being a well versed student of the particular type of bayonet it does appear to me that the original grips may already be a replacement or already altered because of the lack of milling marks to the grips. You have mentioned a weld to the cross guard and if the subsequent repair requires additional work to blend the repair or a significant radical change to the entire appearance occurs I would use the new grip scales. Only you can decide, but if it were my project I would maintain the current grips and use the NOS replacements only in the case of significant damage or to replace a part that is not entirely serviceable.