With closer inspection I can now see that they are indeed dovetail joints but you still need to glue them. I use clamping blocks with hollow sections to fit over the pins and tails for both sides of the joint on each corner. It also helps to use a glue with extended open time and blue masking tape on the inside corners for squeeze out. They make a beautiful and strong joint but really tough to glue up. Especially if they are a little tight.
Nice job on the boxes and joints.