Good point, can't use that magic Mig21 radar doing Grom
War Thunder forums seem to kind of contradict the other source I mentioned, here the SM is just some quite "new" Serbian model:
https://forum.warthunder.com/t/mikoyan-gurevich-mig-29-fulcrum-history-design-performance-dissection/28118
Though Wikipedia also mentions the 9.13 Fulcrum-C SM as a main variant.