heater core box holes... stock or modified?

[jks67ss396]

Hi guys

I am replacing my heater core and have always wondered about the larger hole in the heater core box. The holes are where the heater hoses from to/from. Im starting to see pics of where those holes appear to be oval rather than round. Are they oval/enlarged/too big for the hoses right from the factory? My trucks previous owner (PhD in hack jobs... got most worked out covered the holes with "mylar tape" like he was trying to hide their oval-ness

Can you guys confirm the oval shape?

thanks!