Do academic oral historians have the same legal protections as journalists?

No, according to the U.S. Department of Justice. This is from Peter Klein at the Organizations and Markets blog. He writes,

With the filing, the U.S. government has come down firmly on the side of the British government, which is fighting for access to oral history records at Boston College that authorities in the U.K. say relate to criminal investigations of murder, kidnapping and other violent crimes in Northern Ireland. The college has been trying to quash the British requests, arguing that those interviewed as part of an archive on the unrest in Northern Ireland were promised confidentiality during their lifetimes.

This is from Inside Higher Ed via Zachary Schrag, who notes that the DOJ brief 

suggests that the Boston College researchers are mere academics, and seizing information from them should be easier than prying it from reporters “because the Constitution and the courts have long recognized the unique role which news reporters play in our constitutional system. See, e.g., Branzburg, 408 U.S. at 681; New York Times Co. v. Sullivan, 376 U.S. 254, 268-71 (1964). The limited protections afforded news reporters in the context of a grand jury subpoena should be greater than those to be afforded academics engaged in the collection of oral history.”

There are a lot of interesting issues here to do with informed consent, academic freedom, confidentiality, etc. One wonders what effect this could have on oral history if the British government gets the information it wants. Clifford M. Kuhn, a historian at Georgia State University who is also a past president of the Oral History Association, noted that,

"Trust and rapport are at the very core of the oral history enterprise," he said in his brief. As part of the process of "informed consent," interview subjects request certain levels of confidentiality, and researchers approve them. "The reason for this protocol is to foster candor and openness in the interview itself, so as to most fruitfully and fully enhance the historical record."

If researchers can't make such pledges, Kuhn said, they may face "self-censorship during the interview." He added that "if promises made by a repository are not kept to narrators, there might be a damaging ripple effect on potential future oral history interviews and projects."

People respond to incentives, and confidentiality is a big incentive in things like oral history,