Trunk extension replacement

new to all this and have never replaced any body parts before but ready to learn. My 73 swinger needs the drivers side trunk extension replaced. Previous owner blew a tire and split it all open pretty good. See pics. Pretty sure I can easily bend back the part of the inner wheel houses where the inner and outer meet. The trunk extension is pretty bent up. My question is will it be easier to try to pound it all back into place or just replace the extension? The paint on the outside looks good so hoping to not screw that up pounding away on the extension inside the trunk. Is it just a matter of wire wheeling it all clean and drilling out the spot welds and replacing with the new piece (spot weld that one back in) Sucks because the panels are all rust free original. Again, I’ve never done anything body related but it seems pretty straight forward. Thanks for any and all help! You guys are the best!

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