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Joe_G.I'll just add that the grading companies do make a modest attempt at keeping registries of the cards they grade. These registries can be searched in several different ways including by year. Because N172 Old Judges began in 1887 and no checklist to date lists them by individual years (1887, 1888, 1889, & 1890), the grading companies likely decided to simplify it to a single year designation of 1887. Increasing this to cover the four year run "1887-90 N172" would be an improvement but still misleading as the card submitted in each case can be narrowed down to the exact year it was produced.
The most accurate approach would be as you suggest with the exact year. This would however likely result in a couple issues including more mislabeled cards and can you imagine the Rookie card collectors now feeling more compeled to find a "first year" issue as opposed to a single copy from within the 4 year run. Maybe that is just what Hal and a few others need, a new reason to seek out some new material 
Regards,
Joe Gonsowski