well, you are off and running. These are great knives to make. You can always just pin rear bolsters through the sides like modern knife. That was traditional, too. Or weld on a stub to use, or file away material on the end of the handle to create a stub in the rear or even two stubs to use for peening. Any of these are historically correct.
Wrought iron is great, forges wonderfully. The only problem comes when you try to stretch it (like with swaging a guard into place). It can't handle even a third of the stresses that mild steel can take, due to impurities. It will just tear, and ruin