I'd say it's more likely to be a damaged foresight. Before you try bending things, take a look and compare yours with other examples in, say, The Vintage Air Guns Gallery. It may have been dropped at some point in the past or someone may have done some DIY trying to increase the range. If the front sight is shorter than it should be, the barrel will point higher when you aim. I've had exactly this problem with a Falke 70 which has lost the very top of the foresight. At the moment I have a bit of plastic rod epoxy'd on top to make it taller. Not ideal, but I can shoot it now. Depending on what your rifle is, a replacement foresight may be available from Knibbs, Protek or one of the others.