Der Reichsrevolver und seine Varianten by Heinrich E. Harder is THE reference. That hardcover is in German, with English subtitles for the pictures and chapter summaries. Yes, all true M1883 Reichsrevolvers are pre 1898, with a few caveats. Production ended in 1896 with both Erfurt and SUHL having just transitioned to producing the second version, which has the raised cylinder stop lugs.
I would like to find a rougher second version.
SUHL, the second largest manufacturer after Erfurt, for some reason didn't put on date stamps. Since officers had to privately buy their own M1883s, some of those were double action or with other modifications, sometimes by Dreyse. Mauser made a small amount also. There were plans to create a much more modern revolver but that was cancelled by the technological jump to the Mauser C96.
In 1907 an "einige wenige" (sound it out

, actually thought to be just a handful, all date stamped 1907) amount were produced by Erfurt for showing for potential foreign sales. The 1907 ones have a different cylinder and would be double action. Of course the Belgians and various commercial German arms manufacturers made some similar but not identical M1883 copies, often lacking date stamps. The key I think is to look for the German military test and acceptance stamps if the pedigree of the revolver is in question by not coming from one of the four major German factories. There were a few smuggled out unstamped 'lunchbox specials' but all those would be pre 1898.
Other than charging federal and provincial taxes and handling, our CBSA had no issue with the SUHL Reichsrevolver I imported from the USA (formerly known as 'the land of the free and the brave'). USA antique firearms dealers will directly ship firearms that are classified as 'antiques' in both countries, while mainstream firearms dealers and private individuals now mostly seem afraid of overreach by the USA security/government agencies.