If you do searches for 3d printer agencies and laser scanner agencies in you local area or country you should be able to find a combination who can accurately scan an original item and then input into the printing.
There may be a need to tweek the cad files but the mtm knobs I recall are pretty tiny so you are at scale of 5:1 rather than 1:5 when printing on paper for a 2d drawing.
it's a topic I'm interested in for jewellery design myself - the cost of the printers and the scanners preclude hobby and small scale so it'll be agency I think
DP