Metal printers are now under $1M, I'd be shocked if SRAM doesn't have one, or at least quick access to one. The cost is probably a small fraction of their overall R&D budget when you consider the full SRAM family.

3D printed metal parts have two major advantages:

1) Rapid prototype testing.
Setting up a full tooling for manufacturing is relatively complicated, and can be quite expensive initially. BMW uses 3D parts for testing certain parts without doing a full tooling setup. 3D printed metal parts are structurally indistinguishable from machined (within a few percent on mechanical properties). I'd bet SRAM uses some 3D printing for development.

2) Impossible structures.
Things like the lugs above, one piece cassettes, interlocking structures, material removal. If you want light weight, 3D printing is the way to go. Even injection modeling has limits, since the part has to be extracted from the mold.

Both have uses in the bike industry. The first just simplifies R&D, the second will take longer to develop because you need a 3D printer production line.