Sort of. Yes, he was a LW at even strength during his most productive years, but the bulk of his scoring those years came on the powerplay. His even strength production didn't really change all that much between LW and C. His initial decline occurred because his PP production went down.
To me, the best he ever looked at even-strength was on the Chimera-Laich-Ward line while it carried us for a while during Ward's first season in Washington. Then everything went to hell that season, Bruce was fired, and Laich got promoted up the line-up due to the Backstrom injury.