You will have to be a little more specific. Are you talking about companies traded on the stock exchange? Companies with more than or less than 25 employees?
About 47 pages worth. See related link
In the US, the BATFE.
Unknown. There are a dozen or so big makers and a lot of smaller ones that don't get reported becasue they don't have to.
No, but you need to be the legal owner of that firearm.
No way for us to tell from a serial number alone. Serial numbers are NOT unique to any one firearm.
No such firearm model number
If it was a firearm originally manufactured without a serial number (serial numbers weren't required on firearms in the US until the passage of the Gun Control Act of 1968), then no. However, a firearm which originally had a serial number and had it removed - very much illegal.
it is a number
There are 259 surfboard manufacturers in the U.S.A.
535
100
435