Would be interesting if they are Slingerland lugs. I have a few drums with those lugs on them and the scalloped peaks are more pointed. The lugs on drum in question the scalloped peaks seem wider at the tip and slightly rounded over. Hard to explain but this pic might help. It shows the peaks are sharper/pointy. I have both the longer bass drum size 3" and the shorter tom size and both are the same shape. Maybe there was another version of them I don't know about? Anything is possible.
I had spotted this too, but I wanted to believe they were vintage Slingerland lugs, but I think I knew they weren't. This drum has a label on it from a music store that went out of business in the 70's which in my mind is cooler than having the original Sonor label on it. This is a drum that I will harvest for parts I got it on the cheap.