I don't recognize him at all for a U.S. manufacturer & I keep up on glass animals. If he is a bookend the only manufacturer who is even in the ballpark design wise with that upright would be Viking as they did do a wide variety of upright standing animals including many dogs, but as of now that one has not appeared. Boyd, L.E. Smith & Mosser are not in the picture either. There is one wildcard & one never knows what they produce until well after something appears, Corning Pittsburgh (automotive glass) makes glass animal bookends from molds (and nobody knows where they get them) for charity purposes, boy & girl scouts, campfire girls, big brothers, etc. buys them at Corning's production cost & resells them to make money for their organizations, but so far that one has not shown up.