That phaser is nearly shaped like a weapon enough for him to recognize it as such! It's actually the way that he's holding it that makes Han fairly certain that he could fire it. Why is it so sleek? So if you throw it in frustration, it cuts through the wind better?

He'll take his DL-44 any day over that thing.

"Han Solo." He says, putting away his piece into his thigh holster. For now. As for the ship ... "like any ship worth calling claiming for yourself, she's got me though plenty of flights that could have ended badly."