Are these usually a certain model or do many models have knockoffs?
theres knockoffs for most of the line, depending on where you get them. these days amazon has done a pretty solid job of filtering out the fakes.
but you can still find them on wish.
there's huge red flags out there, mainly being the price point per model, as well as of course the serial # issue. just like everything else in life - if it seems to good to be true, it probably is.
nobody is gonna sell a real leupold $1000 optic for $400. just like the fake trijicon ACOGS that sell for $150.