If the firewall has right thrust offset, it will typically have the engine positioned as on your firewall. However, the purpose of the off center mounting is to allow the offset to position the prop at the true center. In your photo, it appears that the prop shaft is NOT on the center. Is it just the camera angle? As you look down onto the engine from above it, do you see any thrust offset, and is it positioning the prop at the center line?

If it is not so, you have a couple of ways to go. If your set up is a squared firewall with no offset, fly it that way to see if you like it. If you find it needs right thrust, put spacers behind the left side mounts and see how it flies (also to see how the front of the prop shaft moves more to center).