The reason you have not found it is because these beds were not made by a furniture company or mfr as most think !! They were produced at a foundry or metal fabrication company !! they were then sold by a furniture retailer !! The part that has the J&M mark appears to be cast iron !! Can`t tell if its solid or tubular !!
Back in the late 1800`s and early 1900`s there were many small foundries in almost every major town !! Many of these either closed or were taken over by larger foundries !! There are really few records of these small foundries !!
Your bed is a fairly common type used in many country homes with a value of about $250. to $300. with the side rails !!