Snowman Dinnerware

We went through our Christmas orders today and found a piece of table 32 the snowman set by Thompson Pottery. This link shows this set it is: http://www.mimisbackporch.com/catalog.php/bluebird/ct/pd1393727/Snowman_Blue_Speckles_Sky_Christmas_Dinner_Plate_by_Thomson_Pottery_Retired
Does anyone know if it is dishwasher?

Turn it over and look at the back.

If nothing is there, I wash by hand to be sure