1973 was the first year I bought Topps baseball packs, too. You have to remember they were doing millions of cards over the course of the print run- some were bound to be less-than-perfect. I would probably say that if the sides are noticeably rough cut, you would have a harder time getting someone to buy them, hence hurting the value.
And good luck finding perfectly centered 1973 Topps. The photo, along with its black border, takes up 2 inches. That means a perfectly centered card would have a quarter-inch on both sides.