Your local library is a good place to start. Literally hundreds of books have been written on the history of firearms.
he invented the first handgun
Can't be answered as asked.
Go to Browning.com
Look for a book by Dieter Marschall
Impossible to answer without a detailed description of all markings
Library, Blue Book of Gun Values, Standard Firearms Dictionary.
10-10000 USD depending on specifics, history, accessories, engraving, etc..
If you have a handgun carry permit, definitely. The handgun carry permit covers "any handgun that you legally own or posses."
why can you get a shootgun at 18 but not a handgun
A regular handgun, no. There is no registration in TN.
You can get a letter from Colt. It will cost from 75 on up depeding on specifics. Check their web site.
Which handgun law? Georgia, as well as every other state, has hundreds of handgun laws.