Legal advice on how to check if a design patent/copyright has expired.

BernardMarx:
How long do trademarks last...

https://www.lmgtfy.com/search?q=how+long+does+a+trademark+last

...for on the look of a product?

Makes no sense. I suggest you spend some time with Google / USPTO...

https://www.lmgtfy.com/search?q=what+is+a+trademark

http://www.uspto.gov/trademarks/basics/