Bluehawk,
Take a look at the following pictures of:
a. Barrel stamping on the Model 1880, you will note the "PAT'D JAN. 20, 1880" stamp under the company name/address stamp, hence the term "MODEL of 1880" used by collectors. This patent was granted to Peter Holter.
b. Comparison of the Model 1880 vs. an early 1st Model 2nd Variation AMERICAN DOUBLE ACTION.
There has been quite a bit of erroneous and incomplete information published in various "guides" concerning H&R firearms. Much of this "data" has been passed down over the years and not corrected due to a lack of collector interest in H&R firearms. Over the past 15 years that I have developed my collection of H&Rs (I have owned over 600 examples, and currently retain right around 400 examples), I have been able to detect the erroneous information and ALSO have become familiar with several top notch collectors of H&R firearms, either niche models or all models. I have also been associated with William "Bill" Goforth (author of THE guide on Iver Johnson firearms) who decided about a dozen years ago to also author a guide on H&Rs. He, Bill, performed historical research using patents, catalogues spanning the years mid 1880's thru 1986, and other published/unpublished sources. As Bill came up with written data, I was able to find examples of hardware to confirm, deny or embellish that data. Several other collectors were also involved, but I had the largest and most comprehensive collection available to Bill. (I personally know one gentleman who has a much "BETTER" collection of H&Rs than I. He is a former employee of H&R Arms Co. and has possession of production records including dates. I have been unable to tap into this source due to confidentiality concerns, until Bill's book is published, and I will honor those concerns.) The culmination of this research will be detailed in Bill's book to be published, hopefully, in early 2011. With his research in hand, he and I collaborated to revamp the H&R Arms Co. section of "THE BLUE BOOK OF GUN VALUES", by Steve Fjestad. For the most up-to-date information, including average national retail valuations - you can read our updates, starting with the 29th Edition. There will be some more updated material included in the 32nd Edition, due out in May 2011 - some based, chiefly upon more "hardware" that I have acquired over the past year, which changes some data, as well as information provided by contributors and posters to about a dozen forums that we both regularly visit and post upon. I hope this info helps - especially if you, or anyone else, are interested in beginning a comprehensive collection of H&R handguns.