Sounds like the rear stud simply got stripped out during assembly. If you call Savage I'm betting they will send you a replacement stock free of charge. Have your S/N ready when you call.

As for the scope, how do you know it was the "wrong" scope? All their literature says is "3-9x40mm scope." Doesn't mention a specific brand or model. Most of the rimfire package guns come with an el-cheapo Bushnell scope while the centerfires rifles always got el-cheapo Simmons scopes until this year when Savage launched the new "Trophy Hunter" package guns which are fitted with an el-cheapo Nikon.