This patch builds reproducible, although that was also the case for me
with the previous Node 6.3.1. patch. It would be great if someone could
verify this.

This patch supercedes the 'gnu: node: Update to 6.3.1.' patch at [0].

Thanks,
Jelle

[0]: https://lists.gnu.org/archive/html/guix-devel/2016-08/msg00816.html