Not really. Content-addressed implies that if the content changes, so does its address, such that returning a different result for the same address is a hard protocol violation.
Having a content hash as (part of) the address is common way to this.
IPFS multihash is a well-known example. As opposed to HTTP.
Isn't that almost what the nix file already is while being legal. Having a cache of all build files is not legal to do.