I had an Emco Maximat and the chucks were re-badged Pratt Burnerd chucks. There is a possibility that Emco manufactured chucks in-house, but it's more likely they went through a manufacturer and re-badged the chuck. Either way, the quality of anything Emco carried was top notch so for 150, I would say go for it. Just make sure the scrolls are not stiff, and that the recess that takes the chuck key is not cracked. They crack if worn chuck keys are used because the cam-out stresses them in the corners were the material is thinnest.
Paul.