Library, appraisal, old gun catalogs
Need make and model. You cannot identify year of manufacture even with the make and model on most firearms.
no
Blue Book of Gun Values
Has nothing to do with firearms.
Firearms makers.
No
Unable to answer without a LOT more information- if then. Many low dollar Belgian firearms have very few records.
The Complete Catalogue of Firearms or The Gun Trader's Guide are two good references. You can also send me a message using the message board here with all information on your revolver, and I can check my references. However, some guns have little public information available.
Insufficient information to answer the question. Identify the item in question and resubmit.
Ruger's website lists the current offerings.
Firearms International was an importer, now out of business I believe. It is unlikely that they would have actually marked the gun with their name before these markings were required in 1968. There are probably other markings that may identify the actual manufacturer. Double Action refers to a revolver mechanism and I have no idea what you mean by a doubleaction trigger on a rifle.
Insufficient information to answer the question. Identify the item in question and resubmit.