I also have a 1908 model 645, which is quite a nice watch (abeit with a damaged dial). As with my other 1908, this is a great watch for everyday carry. It came missing a second hand, but I transferred one from a broken waltham model 1899 (need to be careful about how hard you press things onto the 4th wheel pivot). 21 jewels, adjusted to 5 positions, serial 17166768 - so it was made in 1909; making it over 100 years old and still running fine! Gold center wheel and jewels in screw down settings, but that do not look like gold. A very nice watch and running fine after 100 years.
Then I acquired a model 1892, 18 size, 17 jewels, Appleton Tracy, "P" grade. The movement in these model 1892 watches is spectacular, maybe the most beautiful pocketwatch movement there is. My Appleton Tracy has a broken pivot, and I purchased an amazing 1892 Vanguard movement to replace it (the capstones on the pivot are faceted diamonds!).
Just for some perspective, the civil war took place from 1861-1865. The first transcontinental railroad was in construction from 1863 to 1869. The latter half of the twentieth century was a time of major change catalyzed by railroad transportation. A terrible train wreck in Kipton, Ohio in 1891 brought about a standardization of railroad timekeeping that stimulated watch design. The Waltham model 1892 actually hit the market in 1892.
The term "Vanguard" was originally the name for the 1892 movement, but later was used to refer to a grade of movement among other 1892 grades. The five most important grades were:
I followed the bidding on a nice Crescent Street in 12/2012. It sold for $304 - which seems to be the going price for these watches in very nice condition.
Tom's notes / tom@mmto.org