Rising Storm free with Red Orchestra 2 GOTY?

Red Orchestra 2 was split into Singleplayer and Multiplayer.

Yeah, but you can only use the basic loadout in Rising Storm games, afaik.

Enter the game and you'll have the opportunity to play RO2 multiplayer AND to buy Rising Storm. It's an expansion to RO2, so they use the same library entry / launcher, server browser and so on, but you need another licence for actually play Rising Storm.

You can play RS but only as Rifleman.