5 to 10 years ago I would have paid $1400 for an excellent condition one (that's about what I sold my last one for about the same time back)
Now with the Nodak lowers and especially the WK180c at under $1K, I wouldn't pay more than $1K for a used one regardless of condition.
The design of the 180c is twice the quality and value of any old 180b with likely thousands of rounds down the pipe and no parts support for over a decade of use between multiple owners.
Don't get me wrong, I love the AR180 design. Actually I prefer it over the AR15 by far. However, with all the current offerings of NR black rifles on our market these days and a new 180c that is twice the gun any 180b ever was, it is not the rare Canadian unicorn rifle it once was. 10 years ago it was one of the only true NR black rifles. Those days are long gone now. XCR-L, Tavor, T97, Kel-Tec 16, SG542, WR762, T81, 58x series Mini14 etc etc all available for less in either new or second hand condition.
You would have to be smoking drugs to pay $1,600 to $2,000 for a 180b these days IMHO.