FIE imported various arms made by various makers.
Colt
Gun shows, gun shops, want ads,
Gun shop, gun show, want ad
Check Blue Book of Gun Values
Want ad, pawn shop, gun show, gun shop
50 USD
gun shop, gun show, want ad, pawn shop, egunparts, MidWay USA, Brownell's
Not in any of the gun books I have part of one
Probably not- sorry. FIE was the importer, guns made mainly in Germany. Company is long gone, and my main source for obsolete parts (Numrich gun parts corp) has none for that gun.
Firearms Import & Export imported guns from Italy from about the early 60's until 1968 ('68 Gun Control Act barred import) After that, FIE assembled the E27/GT25/Titan from 1977 to 1989 from parts manufactured by Tanfoglio in Italy. Early receivers are stamped Italy as opposed to Miami FL. FIE went bankrupt in 1990 so you wont be able to research the serial number.
At a gun shop or gun show. <><><><> Additional- FIE was an importer of mid to low quality firearms, and is long out of business. Despite the name, none of their .25 autos would really be a "best pistol". Walther, Browning and Colt did make good quality .25 autos.