On the season finale for 'Bored To Death', there was one visitor to the Brooklyn Comic-Con who was in a costume that wasn't based on comic books or movies. If I'm not mistaken, his white collar and black jacket marked him as a classic TV character from the 1960's, and this could have been the same age as that character today. So to avoid a Zonk, I'm going to suggest that he actually was the TV character, out for the night and enjoying himself at the comic book convention.
(He'd be visible right after this moment, when Ray collapses across the table.)
I haven't been able to track down a picture of him in this episode, and with my limited resources, I can't find a way to make my own screen capture. But if you still have a copy of the episode ("Super Ray Is Mortal!"), you'll find him in the Brooklyn Comic-Con scenes near the Super Ray autograph table - off to the upper left, after the attack on Ray. He's wearing a large, round white collar, dressed in black otherwise, and his hair slicked back.
I'm going to say it's Eddie Munster from 'The Munsters'. Not just a convention visitor dressed as Eddie, but the actual werewolf. (A grown-up Eddie Munster was seen once before - but over in Skitlandia, where he was played by Ben Stiller on 'Saturday Night Live'.)
You can't hit me with the argument that he should be in Mockingbird Heights. I'm about the same age as Eddie Munster, and I was in Connecticut back then. If I'm in NYC now, why can't Eddie be as well?
That he should be still dressing the same way as he did as a kid, well that's just sad. Not like me - I used to wear T-shirts, dungarees, sneakers and today I wear....
So I'm sticking to that splainin - we're seeing the actual Eddie Munster out and about in Toobworld after forty years.
And as for the recasting, Toobworld Central always makes allowances for the aging process.