Related to Nathaniel Hawthorne's The Scarlet Letter, do you believe that if Hester was a man, she would have been treated/punished differently?

One could certainly argue that if Hester Prynne were a man, she would not have had to endure such public humiliation and social isolation as the result of her sin.
An obvious reason for this is that if she were a man, Hester would never have been able to get pregnant as the result of an extramarital affair. Therefore, like Dimmesdale, Hester could have kept the sin a secret from everyone without the risk of being exposed by her own body.
Alternatively, if Hester were a man and was outed to the community as an adulterer, I still think the punishment would have been less severe. The sexual double standard existed even during the Puritan days; women who had extramarital affairs were considered lustful temptresses, and the men with whom they engaged in these relationships were often thought of as victims of the seductress's womanly wiles. As a result, men who were accused of adultery would be pitied as well as judged.
This is proven after Dimmesdale exposes himself as Pearl's father in front of the townspeople just prior to his death. Although the people are shocked, they also feel sorry for him. The text describes the crowd's reaction in the following quote:

The multitude, silent till then, broke out in a strange, deep voice of awe and wonder, which could not as yet find utterance, save in this murmur that rolled so heavily after the departed spirit.

In the following chapter, the narrator explains how certain witnesses to Dimmesdale's death insist that Dimmesdale only made his death a "parable," and he was in no way possibly guilty of the adultery of which he proclaimed he was. This reaction further cements the notion that men in this society were not blamed as much as women. The lengths to which one could rationalize Dimmesdale's innocence is predicated on his respected position as a prominent man in the community.

It might be said that the entire thesis of Hawthorne's The Scarlet Letter has to do with condemnation of the so-called double standard by which men and women were judged in his day. Both Arthur Dimmesdale and Hester Pyrnne are equally guilty of adultery, but Hester has to bear the disgrace and punishment all alone. However, it should be pointed out that, although women were not empowered to impose punishment, they are represented as being far more vindictive towards Hester than any of the men. Here are a couple of examples of women's feelings about adultery:

“At the very least, they should have put the brand of a hot iron on Hester Prynne's forehead. Madame Hester would have winced at that, I warrant me."
“This woman has brought shame upon us all, and ought to die. Is there no law for it?"

In the long run it is Dimmesdale who is punished more severely than Hester, because he dies as a result of his sin, whereas Hester, the stronger of the two, endures and survives.