There one of the Confuseing guns
Heres my best take on them tho i could have some dates out a little like the 1905 thats a guess.
The very frist models have a Double Address on the Barrels side all are Antique.
Next type have a Two line Address on the Barrels top used from 1865 to 1888 all are Antique.
The next model from 1888 to 1905 or so have One line barrel Address and tho most are made pre 1898 theres no way to really date them,
As far as Ser #s Remy derringers used 3 diget Lot numbers.
So they have like #658 or say #346 as a Lot Number which they just kept doing over and over.
So finding two guns with the same set of 3 numbers can happen.
So the ones with Two line barrel addresses are for sure ALL antique (i have goten RCMP letters on the Two line ones.)
the 1888 to 1905 One line address ones could be Antique theres no way to prove one way or the other.
Still they cant say there not antique either. they can not prove there post 1898. or you prove its Pre 1898. so there in limbo Antiques

Lotsa guys have the 1888 to 1905 ones tho as Antique there just hard to import. I have imported a two line address one once.
Then theres a few more modern models with one line addresses as well right up till the 1930s i think they made theses. the modern ones have deeper slanting Addresses all one line. some words or letters changed to.
Very well made and lotsa fun to shoot! everyone should have one or two of theses...