actually I believe all of those laws changed Jan 1 of this year. My friends that restore old Mustangs bought one that hadn't been registered in like 18 years and found out the hard way they apparently assess fees back for 10 years now and you have to pay them.
I just bought a 66 Nova out there from a guy that bought it earlier this year and it had sat in a body shop for 12 years. I have the registration paperwork that shows he paid fees for 10 years and they set the date from Jan 2 2003 to Jan 2 2013, I am guessing that is because Jan 1 is a holiday

I bought the car and just had to pay transfer of title since he already dealt with that issue.
I think your best bet is to call the DMV and ask someone directly to be sure, but I have two data points that show it is 10 yrs back fees now, in both cases cars that sat non-op the whole time. I do NOT know however if either party made that clear or had some sort of signed paperwork as others have suggested, just know what they dealt with in terms of fees to register the vehicle when they transferred it.