How can i handle sampler2D when it is empyt or not set in GLSL

I have a problem from a previous solution for this.

Basically when i dont have a texture for something i just bind a white texel and it worked so far with forward rendering. Now that i moved to differed rendering i have problems with specular texture because when i have a white texel that means the whole surface is specular and the whole light is just screwed up.

Is there a way to fix this problem where i just dont set a texture and do that check in the shader or i can just add secular texture to all things that i have and then export the model.

Note: When i tried something like an if in shader i just got black screen because there was no defuse and no specular texture to tell the light shader what to do.