The first one looks authentic, but something's bothering me about it. I can't put my finger on it Probably from looking at all the forgeries. Lol.
Second one, with Billy Martin. No question. Very authentic. Nice.
My observations: In the photo, the “ickey” part is uncharacteristically small compared to the M, and in the second one, the “M” in Mantle” has three humps which I’ve never seen before.
although this is close in my novice opinion, I must say both signatures have characteristics I’m not fond of
there are way better mantle authorities then myself so let’s see what they say