How was this part made

[Dr Stan]

Extrusion is also my #1 conclusion if the production quantity is high enough.  It probably is if one assumes the extrusions are along the same lines as those used a lot in automation.

Lost wax casting is my 2nd guess.  However it would require broaching the sq hole to keep the corners nice and square.

In either case all the holes would be made in a secondary operation(s).