I think you will find, amongst the older generation, we tend to look at things completely different to the modern generation.
We look at things because of their interest and historical value rather than their worth.
With regards to restoration, your engine basically was worth nothing and wasn't worth getting back into a running condition, but as I said before, it was a very good example of naive workmanship that does not happen much nowadays, so in my eyes should have been left as it was, completely untouched.
But on the other hand, if the engine was a good example of engineering prowess or interest, and was is a dilapidated condition, then yes, bring it back to life so all can appreciate it as it should have been.
You will find that Steve (Cedge) restores old engines of the type I described, and he does a wonderful job of bringing them back to life in their full glory, as they should have been. Just good engineering practices to replace missing or damaged parts, and a good spruce up. Nothing over the top.
I was involved in a similar incident a while back on another forum, where I went a little too far over items that had historical interest and values, and don't want to go thru the same thing again on here if I can help it.
I have many items in my possession from bygone eras, some worth rather large amounts of cash, some worth scrap value only. I have attempted to pass some of them onto museums, but they could not accept them as gifts, and I wasn't willing to take money for them, but other stuff that I have offered, have been refused because there are just too many about, but I just can't bring myself to destroy or discard them because not only to me, but others who have seen them, they are marvels of a time from the past.