Register box insulation inside or out?

I am not 100% sure I am using the term correct, but I am speaking about the box where all the tubes connect to. I will include a photos below.

Anyway, my old system had insulation on the inside of the box with aluminum exposed. My new system has insulation on the outside and inside is bare. Which is better? Does it even make a difference? One company said its better to have insulation on outside the other said inside of box.

Thanks.

I cant seem to post image links yet since I am new so will include url below.
Old:
postimg.cc/ns5D5PJN
New:
postimg.cc/2bsnqX9n

source https://hvac-talk.com/vbb/showthread.php?2226336-Register-box-insulation-inside-or-out&goto=newpost