I would say so yes. For someone who was so incredibly powerful the Pre-Crisis Superman did show consistently that he had minimal resistance or tolerance of Kryptonite and Magic. In the modern era it can vary from writer to writer but without a doubt the modern-age Superman has consistently shown he can push on through the pain of Kryptonite poisoning and often resolve the situation he is in. With Magic it varies, but there are many many examples of him resisting it and actually taking attacks that would surely have laid out his Pre-Crisis self... you could argue that because the Pre-Crisis version was so invulnerable, virtually from birth, he had a naturally lower threshold for pain because of it. When you have spent your entire life from birth invulnerable to pain or injury when something occurs to override or bypass your invulnerable state it will hit you probably harder than it would otherwise.
I seem to remember that PC Supes would get weaker by merely flying thru a Magic region, and a Green K ring would put him on his knees...
Currently, he seems to be able to willpower his way thru Green K, as as been shown able to resist it long emough to fight thru it, and he has also been shown table to take things such as Drmins flames and Cam Magical lighting blasts, things could not do in PC days!