Is there anything particularly rare in the Roosevelt dimes besides the 1996 W?
The Coin Collecting for Beginners website (which I suspect has a bunch of useful information even if one is not a beginner) lists key dates in the Roosevelt series as 1949-S, with semi-keys in 1949, 1950-S, 1951-S, and 1952-S. There is also a 1982 error dime which was minted in Philadelphia, but does not carry the P mintmark, and it is suspected that there are less than 15,000 examples of this error.