This looks like a similar lip on the cap as shown in [id=268285706]. That is my number PB17 in the BIG inventory at http://www.berkshireinsulatorgallery.org/catalog_porc_brown.html. The markings were faint on the cap but i'm pretty sure its an OB. the patent date may be 11/19/18, but again i have questions in my inventory so it may be hard to read.