OSHA's Abrasive Wheel Machinery standard at 1910.215 prescribes specific safeguarding, including tongue guard and work rest requirements. However, in that standard, OSHA excludes certain wheel types when it says, "Natural sandstone wheels and metal, wooden, cloth, or paper discs, having a layer of abrasive on the surface are not covered by this section." If wheels meet the exclusion, they would not be covered by 1910.215, but would instead be covered by 1910.212, the General Requirements for All Machines standard.
Section 1910.212 does not address specific types of equipment and isn’t as detailed as 1910.215, but it does require adequate safeguarding for dangerous moving parts. Some state agencies have cautioned against the use of work rests when wire wheels are used on abrasive wheel machinery. It would be best to contact the equipment manufacturer or local OSHA Area Office for guidance.