Every cap I've torn apart has been made like that, even paper caps from the 70s. I'm pretty sure that's an universal construction method for caps (apart for electrolytics which are made quite differently ofc)
That is why I was surprised by the apparent high inductance of the 0.47uf polystyrenes.
We thought maybe it was increased stray capacitance to other nearby objects, but that would normally cause a taper in the HF response, not a "notch".
From memory, we did try reversing them, to no avail.
As to actually measuring any inductance, we didn't really have anything which could give sensible readings in parallel/series with so much capacitance.
A "Q" meter might have done it, but we didn't have one, & besides, were up to our armpits in mods to use the ancient beasties for PAL colour.
It was easier to chuck 'em in the "odds & sods" box & use some caps which didn't cause the same problem.