RE: Huh.... Floats...
The problem with Gee Bees is that the shape is wrong. When you look at the float from the side, the bottom of the float from the nose to the step should have a curved shape and a relatively flat area in front of the step for the float to run along the water on. The step itself should be straight across, not tapered. And the mounting brackets allow too much side to side rocking. The result is a float that handles very poorly on the water when you try to take off. (They will stick to the water like glue and then put you upside down in the blink of an eye.)
High lift, high powered airplanes like the Fun-Fly types can get away with using them by jumping off the water in a few feet, but any airplane that needs to run along the water to build up flying speed is doomed.
Now, I don't know what seam you are referring to, but fiberglass won't stick to the polypropylene anyway, so I guess the answer to your question is no.
If you have a 3D airplane, go ahead and use them as is. For any other type of plane, carve something out of packing foam. It will work better than the Gee Bees. (And cost less too.)
Jim