David - I have no expertise in Santana signatures but previously posted a likely authentic Santana item which may be helpful for comparison. My example likely dated to around 1976. Based on my limited knowledge and clear differences in the two examples, I cannot offer an opinion either way on your autograph but hope this helps.
beardog1, Thanks for helping. I just need eyes on this one. After 20-30 years, because of the color and aging of the card stock I think it came from a collection I picked thru in LA. back in the day…The problem is I am not 100% sure. If it did not come out of this certain collection….maybe not so good. That is the problem of being an autographoholic. You find it, collect it, put it away, then try to remember 20 years later.