Id like to repair the rust on my bed if at all possible. only issue is there's a lot of that seam missing especially on the front 2. is it at all possible to weld back together while keeping the structural integrity?

 

It’s hard to tell from the pictures and with the paint still on it but I say dig into it. Start by grinding off the paint and rust around the area (I like to use an angle air die grinder with a roloc and 3m 36grit discs) and just see what you got. Anything is possible with enough time and patience and possibly a little money