I know, right? Must have been some people just wanting to mess with the seller.
I like to occasionally browse sold listings in the Men's Clothing and Vintage sections and sort by highest price first, just to see what people are fighting over. Always turns up some interesting stuff.
If there were vents in the first place, and they were sewn shut, yeah, you can probably have them reopened. If there were never any vents to begin with, though, probably not. They require a significant amount of overlap and there usually isn't enough seam allowance to construct it.