Doubt it - front ferrule plates (if he has one - are loose - no pull on the barrel)
At the breech there will be little effect on the barrel - just the forend, [making it stiffer].
A non free float forend that is stiffer and not wobbling to a different position with each shot I think is a good thing - more group consistency due to consistent vibration - (ala M14 tuning tricks).
A forend locked to the receiver by a scope mount rail is similar to a free float rail locked to the barrel at the receiver - just not as secure and strong as free float mounts.

Good luck with that!
