It's certainly a good lesson in what not to do in order to achieve top price.
Photos I've saved here from previous auction.
https://goo.gl/photos/KByRfi3z6Brmgs1d8
Previous auction here: https://www.classicdriver.com/en/car/nissan/240z/1972/386360
Looking at the photos, it certainly looks like the floors have been patched up, but the rail on the passenger side has rust holes in it.
I'd say this car would be an interesting car to strip back to find the nature of previous work / repairs carried out.
The sale price was around $60k AUD, which is certainly high end of our market for sales here for regular garden variety HS30's. So it's not cheap, but then again not too expensive for an HS30-H, but I think the car could easily cost you a fortune to restore properly and buying a good HS30-H that's been properly restored would probably be a better investment long term.
I'm also not a fan of the wheel sizes and fitment on it.