unfortunately there is no way to find the cell library the cell came from only the cell name.. 

But here are some tips to help administer your cell libraries and  make it easier.

First download from BE USER Forum at bentley's web site a  nice little mdl called Celltool.ma ( or something similar ) it will make a book of all your  cells from their cell libraries and  place each cell and  name and  lib source nicely tabulated A4 sheet sizes in a standard model you can then batch print this booklet to paper or pdf and  distribute it around your  office .. it will also let you export the names and library names to excel.. that way when your looking for MYCELL you can search excel or flick through the book and find the cell.cel you need… will also help in not doubling up on cells…

Second tip if you put a number infront of each cell library file ie 10_electical.cel

or 12_signs.cel then each cell name in that library have the same number ie10 or 12 prefix the cell name then when you data point on a cell it will give you its name ie 10_pole then this means it comes from 10_electrical.cel  and not a pole from 12_signs.cel of course this only works for your company's cells in your drawings not supplied from outside your company… oh and try not to use "shared cells" these type are hard to control changes  as edit one in a drawing and  it will force the same change in all the cells being shared in that drg and you may not want that but it will happen without you noticing if you didn't know that it works that way