Hello Don.
I have found it in descriptions fighting application of tanks IS's.
"In February, 1944 regiments of the break completed with tanks KV's available as a part of Red Army, have been translated on new states. Has simultaneously begun formation of the new parts equipped with cars IS, which steels to be called as heavy tank regiments. Thus it even at formation appropriated the name" Guards ". On staff in new regiments 375 persons of the staff, four tank company IS's (21 tank), company submachine gunners, company technical maintenance, the antiaircraft battery, sappers, economic platoons and a regimental medical aid station were."
http://www.armour.kiev.ua/Tanks/WWII/IS2/is2_3.html
and wiki:
http://ru.wikipedia.org/wiki / % D0%98%D0%A1-2