Do you think these F355 headers have been "rebuilt"?

I bought this 95 spider without getting a lot of info from the PO. I believe I am just starting to understand the F355 header failure problem, that the tubing is inferior and the tubes warp and crack open. I've read some and looked at some pictures.

Here are pictures of my headers. The driver's side has no heat shield and it appears some new tube sections have been welded in, perhaps in mild steel or some other non stainless steel. I say this because I see some rust. On the passenger side, it appears that the heat shield has been welded back on. I'm assuming a similar "repair" has done under that shield and that it has been put back together to protect the more vulnerable items on that side, i.e, the oil tank.

Any thoughts, input or ideas? Don't hold back. Give it to me straight, haha.
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By the way, the odometer shows 45K miles if that makes any difference.