Imo BG is way younger than 77.
That's what I thought FOT SURE at first. When I looked at the first pic (the one where the hoodie is not so prominently seen- usually on the left when both pics are shown together) I thought that it was someone around 30-35. Then, I looked at the one on the right and thought, no he's at least 10 years older than that- 45-55. In the first pic, I thought that it showed his hair and it was dark blonde-light brown. Now I think it's not his hair but a hat or just the blurred vision of the hoodie that can be seen over his head distinctly in photo 2.
Also, I thought that BG's coat was extra large and stuffed with various items and/or layered clothes. I could see indentions around his coat that made me think there was not a lot of fat underneath. Also, BG's legs seemed much thinner and somewhat shorter compared to his torso than RL's body type.
However, now I'm not so sure about the pics at all, and feel they may be too distorted to really tell these things.