Sylvester Stallone is now almost the same age as Mickey was in the first Rocky film?

Sly was born in 1946, which would've made him 29-30 when Rocky was made. I'm assuming that Burgess Meredith was meant to be playing a man older than his actual age, given that he was born in 1907, which means that he would've been about 68-69 when he made Rocky.

I never understood why the filmmakers goofed up so badly when they made the third film. We're told at his funeral that Mickey was born in 1905 and he died in 1981. The first Rocky explicitly stated at the start of it (during Rocky's bout with Spider Rico) that this is taking place in 1975. So what, is Mickey eternally 76 years old in the Rocky universe?