Yes, depending on who made it and if records survived.
You would need to be more specific. You could be referring to the serial number, the caliber, a model number, armory/arsenal markings (in the case of surplus military arms), etc.
Serial numbers do not designate calibers. Look on the brrel to ID the caliber.
Yes, handguns have a serial number.
Usually caliber and/or serial numbers.
Blue Book of Gun Values
No. Serial numbers aer NOT UNIQUE. They are intended to be unique to a given make and model- but a gun can be rebarreled to a different caliber.
as a rule, yes
Impossible to answer without a serial number, maker and detailed description.
i know they were made in the 70's
Nowhere! Serial number apply only to articles produced in quantity, their purpose is for traceability and identification. Serial numbers are a very modern thing, a sure way of telling that you have a fake and not an antique.
G9730255 is not a complete serial number for an antique Singer sewing machine. The serial numbers always start with two letters, which are used to identify the year they were made.
Some manufacturers websites have serial number data available, i.e, Ruger and Browning. Proofhouse.com has serial numbers for Colt Oldguns.net has some serial numbers ArmsCollector.com has some handgun forums.