Hi Taiwo,
From my experience, in general, I would always recommend to check the specifications of all the DCF manufacturers for this dispersion coefficient. In spite of the fact that -80 ps/nm/km is the most standard value for DCF, for standard SMF it may vary due to the requirements for residual dispersion parameter in a particular design. This parameter becomes very important in WDM systems design. The attenuation, which is in dB/km, may slightly vary as well.