DV can be 32 or 48k
Usually, its 48k, and the FCP presets are set up for that, but its possible to record in 32k as well.
Most decks and cameras will indicate the audio sample rate of the tape somewhere. Tell us what model you are using.
If you need to capture in 32k, you can duplicate the DV capture preset and change the sample rate, so you can capture properly in 32k.