Protector Spanish pistol .25acp (the Spanish Eibar region had a myriad of small shop metal works - the shop that turned this out may not have made many anyway before they all folded in pre-WWII)
Ser #: 040
Star model BM 9mm
Ser#: 15xx
Eibar "Liberty" 1924 pistol .25acp (see note above on the Protector)
Ser. #: 161x
Beretta Model 1951 - this one is my favorite old gun; a sweet shooter
Ser#: 020xx
Have some old .22s and .410 shotgun with no serial number, had a Siamese mauser with no serial number. No serial number is not the same as a low serial number.
My friend owns a mossberg brownie which at one point was the earliest known mossberg firearm to be produced.... all for $75 from someone who didnt know what they had. He had no idea he just thought it was neat little pistol and didnt know until he had done some research.
My Ruger American . I've never looked at the number really but I bought it early the first year they came out . I'd think it should be pretty low in comparison to where there at now . I'm sure some day it will be considered VERY low seeing how popular they have become .