You will need to call Browning with the sn to find out
"Belgium" will be stamped somewhere on the pistol, or "Made in Belgium", and it'll list "FN Herstal" as the manufacturer. If it's a Belgian made pistol imported into the US, it'll say "Imported by (importer), (city and state of importer's office)", as well. There have been various importers of these pistols throughout the years, so I can't tell you specifically which name to look for.
25-100 USD without more of a description
Yes
Yes
My grandfather's pistol used in ww1
your colt 25 cal semi-auto was made in 1972.
25-50 USD
Lots of makers made 25 cal pocket pistols. Embellishment may or may not be done by the maker
10-800 usd
About $130
Belgium, 200 USD