That's exactly how my father and I are like.. he never was a father, like you said .. financially,emotionally or geographically.. in fact he is partly the cause for my pathetic childhood etc. Anyway I digress, I don't intend to call my father either.... I used to draw him cards but he never really appreciated it, so I guess... think about it, would he appreciate it? In your case, if he actually asked you about a present... it could mean he might be lonely, realizes that he DOES have a son "oh wow.." and he has *missed out* on that part of his life, this could be all about him OR it could be that he wants to foster a relationship with you now - even if it's been awhile.. ok fine, a long time.
For me, I wouldn't call my father. FOR ME, Things wouldn't change imo, and it's already so awkward..
You have to ask yourself, what you want... if you DO call him - okay what happens? what now? Oh okay, happy father's day dad. HERE i got you this at dollars & cents! What now? Oh .... Oh you were pulling my leg all along? _|_
But seriously, why would you feel like a jerk when he doesn't deserve to be entitled " your father" ?
This is about you and your dad now, so do you want to salvage anything there is in your relationship with him or just let it wilt like a dying flower?
It's your choice.