original heater box insulation locations

[brownbird]

I removed my heater box over the winter to replace the core. It's time to reinstall but I do not remember where the insulation attaches.

Around the top opening of the heater box?
Around the opening for the blower motor?
Anywhere else, on the blower motor assembly itself?

Thanks.

[Nightpath]

I'm pretty sure it's just there to keep ambient nose out. Just pad event you see