No it wouldn't as 737 was certified before the new regulation. It is in the article:
> That earlier 737 NG model didn’t have to meet the current wiring-separation standards because they came into force long after that jet was certified.
Just like with cars - you can drive a car from 70ties without airbags or crumple zones but you cannot buy a new car without airbags as it won't be able to pass the latest regulations.
Imo in this case the main issue is not the safety (seeing how the older planes aren't falling out of the sky) but setting a precedent where the certification authority has missed an issue which is not according to regulation - do the manufacturer gets a free pass or it is their responsibility to make the item according to regulation in the first place and it doesn't matter if it was missed during the certification process.