Guttering joiner patchs, questions????

There was definitely some patches there, by the way there's no paint only surface rust. My 74 duster has no drip rail trim and the joiner piece is the exact measurement of the patch with no paint on my 75 duster. I've seen repro' joiner patches for GM cars available but probably better to make my own, but still can't tell from my 74 if they were welded in.