Are there any Browning knowledgeable people on this site??

I'm looking to learn the difference between the A-Bolt 1, 2 & 3. I was told the 3 has plastic bottom "metal" or a plastic trigger or both. I don't know if that is accurate or how accurate that info is.

I was told early A bolts have lines across the bolt. A bolt 1? A bolt 2 the bolts are are flat in the reciever

OK. The ones I am kinda familiar with are a 2 then.
Are the stocks interchangeable between the 3 of them?