Responsa על חולין 78:36

Response: The Ishmaelites are not idolaters, which would render their offerings the offerings of the dead (zivhei metim). This was stated by the Ge’onim. Although in the times of the Sages their offerings were offerings were the offerings of the dead, as stated in the third chapter of Hullin (38b) and the first chapter of Avoda Zara (32b), even though they were the offerings of the dead, if a Jew performed the slaughter, it is not forbidden, because we follow R. Yose, as stated there (Hullin 39b).