Oakland A's 1972 Signed Baseball Help

[sek122482]

Just picked up this baseball at a flea market and was advertised as a 1972 Oakland A's team signed ball. My first question is does the ball look legit? I know its a National League ball for some reason but how do the signatures look?

Second, I am having trouble determining when this ball is from. It has Mike Epstein and Mateo Alou who were with the A's in 1972 but traded in November. However the ball also has Wes Stock who from what I can tell joined the team as a pitching coach in 1973.

Lastly, does anyone know what the marking is inside the spalding logo that looks like a "25".

Any help would be greatly appreciated. Thanks!

Scott
sek122482@yahoo.com