Ummm, just a few years ago, Trump was on the record in favor of an assault weapons ban and increasing the waiting period for all other guns. So his current 2A stance is relatively new to him, not a long-standing principled position...
So what? His second amendment position paper is published. He’s mentioned it tens and tens of times at rallies recorded by a dozen media cameras. Do you really think he will go back on it??
He also praised as "Brilliant" former NYC mayor Michael Bloomberg for his efforts to use his millions to take guns from law-abiding citizens. And he did that in 2013.
Of course he has a differing opinion now when he's trying to get the conservative vote, but given his long record of being anti gun, he cannot be believed.