I'm always happy to find an an old set of these, and this is both a very old and a very loved set, handmade of pine, with finger jointed corners, found in Adams County, PA. As with old blocks, for me the wear on old sets of nesting boxes like this is very much the thing, here the paint almost entirely worn off the facing edges, nails added to reinforce the corners of the smallest, and a replacement bottom added to the largest. Plenty of soft wear to the paint elsewhere too, especially on the exterior of the red one toward the bottom. And fully painted interiors, too, but for the interior (replaced) bottom of the largest. Wonderful. 

Largest 5 1/4" t x 5 5/16" x 5 3/8". Paint wear and a few repairs as described above. all to the good in my opinion. Very sturdy and sound.