Spectrum precision of fluorescent lamps
It depends what aspect of the spectrum you are referring to. The wavelengths of the different emissions will be identical for all lamps of the same type, since this is dictated by physics (and chemistry): lamps will differ only if they use different working gases or phosphors. The relative intensities of the emissions will most likely vary considerably even for the same lamp with respect to supply voltage, operating temperature, and lamp ageing. I do not think that two arbitrarily chosen lamps will always be positively identifiable based on their spectra, but they will often be distinguishable from each other, at least in a minor way.