The above knife is typical of the knives being shown. Whilst I think this is a really great knife and a great idea, it is not representative of a 18th century knife. Notice the reenforcing rib on the top of the blade. This is 20th-21st century. Yes they still make these shears.
Above, 21st century shears. Note the rib on top of the blade.
16th-17th century shears. Notice these are made in one piece, not two pieces.
This knife above is actually advertised as an early Indian knife on an antique site! Early when!