Mark's it's raining.
After 1912 when the numbered guns (except Deluxe and Monogram) were changed to noun grades like the 00,0 to Filed Grade and Ideal Grade and when they started making box lock guns was because in order to stay in business they had to make lower graded guns to keep up with the market. You still see very few of the other mass produced guns, but in my opinion you see more low end graded Smith's still working fine because they were still hand fitted and all removeable parts were serial numbered to make sure they fit that gun when assembled.
Say what you want.

David