For sure there should be no leakage of contents, so this sounds better. The crystals should be tight against the edges to induce the piezoelectric effect with the heat of your hands.
And as far as I can tell there is no particular need for end caps, other than to hold in leaky products!
$59 is an amazing price, even if they are smaller.
Can you send me a link to that please. Would like to have a look 👀