i'm am building a great planes easy sport 40 and i have a question. no where in the instructions does it say to put on fiberglass wing reinforcement. should i put some on just in case?

You don't need to worry about it. If GP doesn't say to use it, then the plane is engineered to be strong enough as is.

If you WANT to use it just for peace of mind, go ahead and add some, but it shouldn't be necessary.

thanks because i was'nt shore

If you look at the center sheeting you will see it's all one piece, no seam in the middle and there's your strength. No glassing needed.

The canopy/fuselage wing mount also adds to the center strength of the wing. I have seen several of these beauties take a cart wheel with out the center section being affected.
You are going to be happy with the final product what ever you decide.