no.

Non Sequitur, why not?

The name of the firm and the flashiness of the work don't usually matter very much - mainly because admissions committees tend to be more interested in personal academic work than in professional work.  What can matter though are the names of your recommenders - for that purpose someone with name recognition can carry more weight than someone unknown, but only if the well known person knows you well enough to be able to write non-generically about your strengths and why you're suited to the particular school.

Pick the firm where you'll get the broadest exposure and involvement in all aspects of the profession and don't worry too much about name brand recognition or flashy work.

^bloopox pretty much nailed it

If you want improve you application through "work" do things that hippy professors love.  

non-profit work, volunteer work, activism for the right causes, fundraising, etc.  Actual jobs are of little interest.