The Fluke 87 True RMS Multimeter was the first generation of the Fluke 87, and was manufactured from 1988 to 1998. From 1988 until August 1996, the meter used 1A 600V and 15A 600V fuses (Bussman BBS-1 and KTK-15, respectively). Meters that used these fuses are not marked CAT III on the face of the meter near the input jacks.
The fuses were changed in Fluke 87s made in August 1996 and later to comply with the CAT III requirements of the IEC61010-1 standard. Theses meters use 440mA 1000V and 11A 1000V fuses, and the meters are marked CAT III 1000V near the input terminals.
These fuses are not interchangeable; you should use the fuses that were originally used in your meter.