This is for what its worth and unless you send it into an expert per above, the success is hit or miss.
My wife gave me an Ameri San Pao9la 1976 (since gone) NMA some years back she had bought new and shot some. The bolt was not timed right and half **** had it back up and annoying to deal with (partial **** would drop it but prefer the half **** to work right)
Clearly the part of the bolt that indexes on the hammer pin had been filed and in the wrong area (you could see it).
Nothing to be done for it, in the meantime I ordered a Parts kit (Uberti) and the two bolts did not match.
I did a fair amount of sleuthing and what I was seeing was Pietta parts and particularly the bolt looked a lot more like the the ASP (and it turns out the ASP and Pietta have a lot in common heritage wise)
But I had been working on the Uberti bolt and much to my surprise it worked. Mostly it was the bolt end and it had a different shape than the ASP/Pietta.
Once I figured out the Pietta bolt was a better match, I ordered one. It won't work and I can't see the fiddly details inside to see why not.
No one other than a gun smith who works with these could tell you and maybe not even then but the good ones will have the range of experience to know how to fix it.
The older ones went through a range of mgs, places made as they moved around that area of Italy, importers and ..... Nothing stable to say.
Years back my surveyor boss had a new Chevy Suburban that the rear end differential shaft seal started leaking. The local Chevy dealer has a bad reputation. He wanted me to fix it. I told him I would not touch it, anything I did would void his warranty and if the whole rear end went for any reason, he would have to deal with them.
So he took it to his repair shop (I did not do in depth engine or rear ends etc). So, they looked at the Serial Number (VIN now) and ok, this is the XXX seal and took it apart, only to find it was the new ZZZ upgraded seal which they had not seen in that SN range. They did their due diligence, it was well withing the range it should have been fine and it was not.
Where did that leave him? Down for 2 weeks while they searched the country for the new seal. Why would you make spare seals when they are brand new and seals don't fail?
And there in lies the rub, someone can say that this might fit or will fit and it won't. Someone might think it works and does not. You can look at the parts kits and see what is similar and if it fails you can test it (or test before) but its a coin flip and to get it to work if it can you have to file on it.
And a side note, I have a Pietta NMA and the cylinders are longer in it than the ASP NMA. So those do not cross, the ASP cylinder will fit into the Pietta, but there is a big gap at the cone.