It's the Cody Museum that has most of the remaining records - but they don't gass for zip (IOW: wanna play, gotta pay).
http://www.bbhc.org/explore/firearms/firearms-records/
You'll have to pay them for a certification letter, which would also include the original config & maybe when/where it was originally shipped - but I'd WAG your .25-35 actually dates from 1896-7.
.