Oh, as I meant to mention... 1983 was probably on the tail end of the "martial arts craze" period. So swords might have been cheap, or not so cheap. They could have been pretty prolific, and there were probably lots of stainless steel, poor quality ones out there. There were probably some itto, or metal practice blades being marketed as the real deal to unaware or ignorant buyers. As a kenjutsu and iaijutsu practitioner (as I'm sure her stepfather was) he'd know the difference and avoid them. 

On a side note, that home probably has at least two bokken (wooden sword, great clubs and usually focuses blows better than bats). There may be a second katana on the property as well. That one is likely the practice blade, whereas a katana over the mantle may be a much more artistic piece (still real and functional). 

Perhaps something like this: 
[img]http://ryansword.com/rs/jwt64509.jpg[/img]