rim question

[chevysbest92]

hey guys, my PO put on a set of aluminum rims and i went to work on the brakes and put the rims back on, they wouldnt seat on the drums right, its like theyre are 2 little lugs comming out of the drum, are they suppose to be there? like placement studs? or did some guy break the old studs and just put these rims on to make it a rolling chasis? i checked the back of these rims and theres no extra holes for these mystery studs. and also, are the rims suppose to be huncentric or lugcentric? these rims dont sit on the hub, but the lugs are tapered to be lugcentric. just making sure so i dont have a wheel break off on the highway, thanks guys