A former senior Senate GOP aide:

Your caution is well placed, as history demonstrates the Native Hawaiian advocates have used the approps process before.
In late 2000, as Congress struggled to wrap up the end-of-the-year spending package, what should magically appear in the final spending bill conference report but…Native Hawaiians!
The back and forth over how it got in, who was responsible, why it was still in there after opponents had been told it wasn’t going to be, and the convincing it took to take it out is too long and silly to retell, but upon its discovery, Senators Don Nickles and Phil Gramm refused to let the House adjourn sine die and held Congress open until they constructed the parliamentary procedure to strip it from the conference report, and had both the House and Senate pass the provision to kill the bill.