Rusted off bed lips need help and ideas

[GMC1965]

I am planning on fixing what I have here even though its rough. I would like to know if there are any strip panels for this or would I have to make it myself. If so has anyone else done it and do they have pictures of it, I am a new welder (No experience but I take my time and can learn), How would I go at this, Also after welding them in how would I get it smooth and look like it was never done, would polish side things(they go with the rails) cover this up.

Thanks