The earliest 87 has no IEC category rating. Otherwise, I think it is identical to the next version, which has a 1000V IEC Category III rating. This is a 4000 count True-RMS meter with basic DC accuracy of around .1% + 1 count (.2%+2 counts for mA). Maximum capacitance measurement is 5uF. Frequency measurement to 200 kHz. Green backlight.
The 87III is 1000V IEC Category III, 4000 counts. Basic DC accuracy is .05%+1 count (.1%+1 on mV, .2%+4 on mA). Has a 20,000 count hi-resolution mode for some functions. Otherwise very similar to the original 87.
The 87IV is a completely different meter. More like the 187 than the 87 or 87V.
The 87V is IEC Category III 1000V, and is (mostly) a 6000 count meter with basic DC accuracy of around .05% + 1 count (.1%+1 for mV and .2%+4 for mA, 1%+2 for uA). Maximum capacitance measurement is 9999uF. Frequency to 200 kHz. This meter also has a temperature measurement range, a low pass filter, smoothing feature, hi-resolution mode (20,000 counts in many modes), etc. White backlight.
The detailed specifications are all in the manuals which can be found online.