Ron Guth:
With its hefty mintage of almost 4.5 million coins, the 1887-S is one of the more common dates in the series. Like many of the dates from the 1880s, this is considered a generic, type coin, and it will not command a premium for the date. In high grades, the 1887-S is a little tougher to find. Anything above MS65 is considered rare.
The quality of the strike on 1887-S Dimes is generally good to above-average. Occasionally, the mintmark is filled, creating the appearance of a blob mintmark on lower-grade examples.