In previous post I was told to install "Product Attribute Grid" in order to set quantity next to each attribute (thanks to Kobra..)

http://www.zen-cart.com/index.php?ma...roducts_id=876

Since I already installed (my colleague actually) a different attribute:
http://www.zen-cart.com/index.php?ma...roducts_id=310

Can they be installed at the same time?
or
must I Un-install the other addon first?

Thank you!