Passed down pattern

My mother and my paternal grandmother both knit. My grandmother has since passed away, but I'm still able to share my love of knitting with my mom. Recently, she dug out a little relic of my childhood, a hat she had knit when Matt and I were kids.

It is based on a pattern my grandmother had knitted for one of my older cousins whose origins are now lost.

I'd love to adapt this pattern, myself, and offer it up for all of you out there, but I'm a bit concerned that it may be based on a copyright protected design. My mom isn't sure whether this is an original design of my grandmother's or something she worked from a pattern.

It's a fool's errand to try to prove a negative, (i.e. how would I prove that there was never a pattern like this before?) and I suspect that more than one person has ever designed a hat with a clown face theme, but if anyone recalls a pattern from the 70s or earlier, that looked strikingly like this, I'd love to know. If not, I'd like to adapt this into a free a pattern, with some minor modifications.

Modifications? Yes, I know, I can never leave well enough alone, but I think I could design this so the ears are knit along with the hat, and I think it'd be good to make it in a lighter gauge since most of my friends of baby making age, live in warmer climates.

My mom also brought me a big bag of cashmere roving (oh la la) in a gorgeous dusty grey brown shade, but I haven't been able to get a good picture of it. All this on Mother's Day weekend, no less.