Selling your own parts to be restamped as another brand is common though. Selling your brand to be stamped on someone else's parts is basically only useful to do this exact thing though.
Plus, clandestine supply chain attacks fall into 2 categories:
- A. With manufacturer/reseller complicity. (Not many manufacturers choose this because it would harm their business.)
- B. Without manufacturer/reseller complicity, but with logistics interception for sw/hw implants or complete substitution. (This is the method NSA TAO used to load implants into Cisco gear.)