While Bethlehem may have made presses, they also rolled their name into the web of every I-beam and channel they made. Don't assume that the lettering on the channel iron identifies the manufacturer of the press.
Without dimensions of the channels, it is hard to determine the strength of the press. Judging from the bend in the upper channels, the screw can put out more force than the frame can handle.
A starting point for estimating the capacity is to look at hydraulic presses with similar structural components (especially the cross channels that carry the force in the upper frame), and keep in mind that the wider the opening between the vertical channels, the less force they can handle.