Guran ,I am sorry but I disagree, I think there is a negative impact on sound in late Wheatstones,
I owned a Crabb made by Neville Crabb it played well as regards action, it had metal ends[so difficult to compare with my wooden ended wheatstone],but i preferred the sound of all my wooden ended Wheatstones.
The Crabb was bright,but had none of the subtleties of the Wheatstone.
furthermore I had a conversation on this topic, 2 weeks ago with Steve Dickinson, he said to me that the wood used inside the concertina was in his opinion more important than the steel.
Dickinson was scathing about the use of plywood.
with the greatest respect Guran, I know whose opinion I value more, however I do know another maker who thinks that the steel used for the reeds is more important, so there seems to be differences of opinion between makers.
but since I have always found Dickinsons work and his concertinas to be the best that I have heard, until someone can prove to me that it is the steel,I remain unconvinced , I suspect that it might be both the steel and the wood.