The B1 visa has such provisions already built-in:
As a B-1 visa holder, you can temporarily bring goods or products into
the United States to solicit orders but you cannot sell them or make
money in the United States. If you visit the U.S for a business
venture, conference, meeting, trade show, exhibition, sales, etc. you
will receive no salary, or income from a U.S. based company, source or
Source: CBP Website
Further, there is a page on the CBP website which deals specifically with trade imports.
They both state the same - there is dedicated allowances for the temporary import of goods specifically for exhibition, display or sample purposes.
On the CBP Form 6059B (PDF) (the blue declaration form), it specifically states for Visitors (non-residents):
Declare the value of all articles that will remain in the US
As you will be taking the samples back, you do not need to declare their value; however, I would tick "I have commercial goods" (#14) just to be safe.
Keep in mind its better to be safe as missing something due to confusion can be interpreted as deception by omission.