The heatsink fit perfectly (in Model B of the Raspberry Pi), they cover the chips completely, but do not depend on (touch so no additional components). Do they do so because win with a 900MHz clocked Raspi under load, the heat sink quickly to temperature. The actual temperature of the chips I have not measured / compared, however, the heat seems (from) transport yes to work.
What is not mentioned in the description: These heatsinks are "self-adhesive" (DH: You can already attached using "sticky tape" immediately be mounted)