Do you have a reference somewhere that says that? The Wikipedia entry for connectomics does not imply that and I've not read of anything that can get the weights out of neurons.
That is because there are no weights to begin with. In actual biological neurons synapses perform a rather complicated biochemical dance involving vesicles, ion channels, second messengers, whenever an action potential arrives. Some of that can be described by simple ODEs which might contain a constant that you could call “weight” but the actual physical synapses know nothing about that.