Ulmos Tool Saw with Extra Blade

The Ulmos 7 in 1 Tool Saw made by Kingsland Saw Works. Someone excitedly wrote, "Georgia Patent!" on the blade. There is a small crack along the top saw nut all the way through the handle. There is no etching on the blade that is currently attached to the handle. It must have worn off. However, I have an almost mint replacement blade for it with perfect etching on the front and back. The blade appears to be pinned to the aluminum angle guide, but the holes in the replacement blade seem smaller than the pins so I didn't attempt to replace the blade. I was worried I would damage it.