That's not the most ideal fender modification, if they used body filler to cover the weld, be extremely careful when removing it, or the filler could crack between the headlight bucket and the fender. I don't know who built it, but I would take a good look at the underbody for poor repair work.
You can never be too careful with these cars...
These are a couple of good places to get replacement parts
http://www.vintagerubber.com/240z.aspx
http://www.thezstore.com/store/merchant.mvc?Screen=SFNT