Help Is It or Is It Not

Hi,

I am new to posting although I've been a member for about 2 yrs.I posted this before in shopping advise but did'nt get any replies so I thought I would try here. I am looking at what I believe is a 1985 Gibson RB250 S/N 82965568 correct me if I'm wrong. I am not sure about the decal can anyone tell me is it authentic?