Use the Parameter Manager. Sort by Designator, match up all the BOM items one to one, then copy and paste. Boom, done.
Matching up items can be tedious if you have to enter formulas on the spreadsheet, but doing a bunch at a time shouldn't be too bad.
This is the manual way, akin to opening up each component and pasting in the parameters. Just, doing it in parallel. Alternately, you might be able to set the BOM as a database source (using a DbLink file) and get the parameters to import.
Tim