No
In the United States, gun registration laws vary by state. Generally, a firearm must be purchased by the individual who intends to own it, as federal law prohibits the transfer of a firearm to someone who is prohibited from owning one. If someone else purchases a gun for you, it could be considered a "straw purchase," which is illegal. To register a gun in your name, you typically need to be the direct purchaser.
Internet, library, gun shop, gun shows.
Go to the seller where you purchased the gun.
Go the the gunshop or person you bought it from.
Contact your local police and ask them to run the serial number.
Someone who can find a gun on you without frisking
find marks on the cat, find the ammo, or see if he owns a gun
As a practical matter no. You can find out by the sn when it was shipped within a few weeks or a year or so.
Gunsmiths, gun collectors, gun-oriented internet forums, you might find someone at the gun show who'll know something about it.
Someone can find gun cabinets for sale from a number of companies such as Amazon. Amazon has a large selection of gun cabinets for sale from a number of companies.
The extractor for a model 170 Savage Arms 30-30 can be purchased through Numrich catalogs. You can also find this part in the Brownell's catalog available at many gun stores.
There are a few websites where someone can find detailed schematic gun pictures. Some examples of websites where someone can look are Forbes, AR15, and Take Down Guides.