Yes, nice crack!
I have a probable Salvador Ysart weight with an all-around crack and it is still in one piece. But it's smaller than magnum. One of my Salvador magnum 3D Butterfly weights has a full crack across and through the base, also still in one piece.
I have emailed the seller to say that I believe the weight is by Salvador, not Paul and I think it's 1940s/50s rather than 1930s - it fits well with several magnum designs with 3D Butterfly, Upright Flower and other Fountain patterns. Given that the general views are that Salvador was not into paperweights very much in the 30s, and that there are quite a few known magnums like this one (I have five!) I favour the later years.