Most probably not.
There is a limit to the amount of muscle one can put on naturally depending on height/joint-measure and maybe some other genetic factors.
Here's a link to a great article by one of the few most knowledgable guys in the field of nutrition, diet and exercise.
Lyle McDonald Genetic Muscular Potential
I highly recommend reading his articles.
Here he gives 4 models for expected muscle potential for natural athletes, by himself, Alan Aragon, Casey Butt and Martin Berkham (leangains.com)
Arnold at contest shape weighed in at about 230 pounds 5% bf, 6' tall
This is already way over the estimated max as calculated by Casey and Martin, though one could argue there are genetic freaks and one can might make some small gains above ones natural limit though these will come very very slowly. Still, this is a pretty massive deviation from their calculations.
One only has to look at natural bodybuilding competitions to see people rarely come in at much over 200 lbs contest shape. Really no one compares to Arnold or the likes.
There is a very big difference between contest shape and a more regular 10-15% bodyfat. One may be able to hold onto a lot more muscle mass when one maintains at a higher bf level. So there might be natural guys who might look bigger and be heavier than Arnold, but they will look a lot different when they cut all the way down to 4-5% bf