Love detail of the fine ribs/rings around the base in the metal
Those are machining marks from when the cast part was turned on a lathe. If you had the patience to trace them, they would form a continuous spiral around the part like screw threads or a record groove. (Record? What's that?
) The slightly wider groove running at a more noticeable angle is from the return move of the cutter, traversing faster as it returns because all of the material has already been removed.
If someone wanted to reproduce this finish, on a part that had been rust-scarred for example, a competent machinist would be able to do so fairly easily. Preserving stamped numbers would be challenging, but not entirely out of the question depending on the depth of the stamping.