FWIW I think you're reading it right, and no IMO not everyone has been "restored". Calvin did not teach the heresy of universalism. But also, when he talks of the image being destroyed, he is not speaking of an utter annhiliation here. Even the original quoted section mentions "obscure, vitiated and maimed lineaments" that are "remaining in us". The image is totally broken, not totally missing. All mankind, including the unrepentent elements, still retains some part of it.
He's talking of spiritual regeneration, right?
Not spiritual regeneration only, and defintiely not in the context of individuals only. His view on what makes up the whole of the image of God is consirably broader than just an image residing in an individual. Modern evangelicalism, and the Anabapists elements of the Reformation itself, do not see regeneration extending to groups and societies at large. Reformers like Knox and Calvin did, however, and thus for them the whole image of God would reside in the whole of mankind, not complete within standalone individual men. It helps if you make a distinction between Man and Mankind, and also between the original unfallen image and it's current tattered state, when you read the Commentary sections.
So let me see if I can summarize and extrapolate fairly here.
You think that the Reformed tradition generally (for which the OPC is a viable representative) would see the image of God in mankind/and individuals/and groups in their natural state apart from Christ as being retained enough to support the thought that each and every human life is precious in God’s eyes as it bears in a limited sense His image? (It would seem to use this quote in a statement against abortion something like that must be intended.)
Assuming that is a fair statement, I think the nub of the biscuit for the Reformed on Total Depravity is that man (apart from Christ) is a despicable enemy of God. More perp than victim. Perhaps these two thoughts fit together for some but it doesn’t work for me. Closest possible fix is ‘vengeance is mine saith the Lord I will repay’ so the real sin in abortion would be taking the law into one’s own hands or that some of those babies may have been elect so one self-incriminates.
What I don’t see is how the fundamental impulse of the pro-life movement (that every life is a precious (good) gift of God) is not inconsistent with the Reformed teaching on depravity.