How do they get the guts out of sardines?

I’m having some King Oscar sardines in the 2-layer tin. While picking one up, it came in half. No guts on either half. I can’t detect a belly slice. Am I just missing it, because, well, they’re packed like sardines? How do they get the guts out?

I’m pretty sure the same way they get the bones out.

i.e., they don’t.

That’s what I’ve always assumed. But I didn’t see any.

Slice em and goosh around on em until the guts come out, at least according to patent #3407435 (1966):

SHRIMP AND SARDINE PROCESSING MACHINE

Wouldn’t the belly slice be where it came apart in halves?

Likely. A slit belly could easily anneal as protein coagulates during the cooking process.