This is a play on words, you normally wouldn't call it a stuffed animal, but it is technically a stuffed animal. The joke in the comic is that it subverts expectations.
Yes, when I was a kid in CA people would describe taxidermied animals as being “stuffed”
I distinctly remember the parks department bringing in “stuffed” owls and cougars and stuff into class during first grade to teach us about the local wildlife. It was rad.
I got a realistic-looking stuffed animal mouse as a kid from my grandpa. I don't think it was a taxidermy, but pretty real (or to my 5yo brain). I loved it until it unsurprisingly disappeared after I was being a little dick.
When I was a kid, one of my friends got a stuffed puffer fish for his 10th (?) birthday from an uncle. We klater joked "he's too old for stuffed animals," but IIRC, he loved that thing.