This is like a problem for an ethics class or property law...is ownership read with the tag and title, or the car, which could be made of 1000 parts from other cars. We could argue about this all day.
My VIN tag is from a different car than my shell and body tags. Imagine my surprise (and disappointment) when I got my British Heritage certificate and the car as described (tan) did not match the car I bought (red, at least under the carpet). The fellow who runs the certificate department did identify a red car from the body tags, and was nonplussed about it. He said, it is probably a reshell and this happens all the time.
It has a 1275 engine from another car, and who knows what else, what if I put a couple of Miata seats in there, and put some Rostyles on it? When does it stop being the car that is associated with the VIN?
The cells in my body regenerate all the time, so when do I stop being me?

If I lose my passport and drivers license am I not me anymore?
I have a clean title and as far as the law is concerned as long as the car that is attached to the tag matches the title, and that is the car I own.
The PO had had that car for 20 years--or did he only have the tag and title for 20 years? Once, for grins, I did enter the VIN in a stolen car database, and it goes nowhere, because there are not enough digits/letters. Yeah, it bothers me a bit, but WTH am I going to do about it?
Lewmac wrote, "
So, my only choice to get a title appeared to be to find a set of tags with a title, essentially buy another Bugeye body in need of restoration. How often does it happen, that when you really need a part or in this case, a bugeye body or a set of tags with title, that it appears on eBay ?"
But someone did, or does have them in this case. So CLEAH you're saying to Lewmac it would have been unethical to accept them if he could not have gotten to the bottom of his issues. But if he can't legally drive the car, which is its function, isn't the car worthless as a car, in which the car's value is determined not by its pieces but because it has a VIN attached to it that matches numbers on a piece of paper in the possession of him.
Otherwise it is just a pile of metal, rubber, and plastic--and these are given their value by being built for purpose.
Or does the ethical dilemma go away because he is a good guy and isn't trying to put one over on anybody. I don't know but I am sure that the guy who made the offer of title was trying to help out someone in exactly the same situation as lewmac before he got his title. And maybe that is what happened to my car too.
I would never have known if I hadn't gotten the certificate, and what am I suppose to do now, try and track down the person who once owned the car attached to the body tags and find out if the shell they were attached to was stolen and, if so, return whatever parts I can identify as theirs to them? Or maybe those body tags don't even belong to the shell of the car that is attached to my VIN tag at all, maybe they were just screwed to A-pillars that were grafted on from a third car...I don't think you can prove it either way.
This is getting ridiculous. I think I will just stick to what the law thinks, which is that because the car my VIN tag is attached to matches the title in my possession it is mine.
One thing I have to ask everybody is why they think the manufacturer of these cars didn't rivet the tags to the car? This was 1958-60. Stolen cars were not a new thing, rivets were not a new thing, it couldn't have been a cost issue, so what's the deal? Perhaps it was just their assumption that these cars were going to be reshelled so why bother?