This is a nice one and I have seen it recently during the search on the OP, I will do some more digging.
This type did show up in Akro “Gift boxes” usually without any stamp like yours shows (rare). I looked and could not come up with it---maybe a “Akro Ringer” gift set is where I saw it, I am not really sure though.
It is a keeper for sure. Brittle as it may be, put it in the fridge (who cares if it smells like onions). Check it out next spring and continue on with a possibility of it being more pliable—then try getting it straightened out with a slight press between two heavy objects(books). It does take some time.
Marble-On!!