1979 Jenny Lind Baby Crib Parts Request

I’m trying to learn more about an old Jenny Lind–style baby crib from around 1979. Some of the metal pieces that hold up the mattress don’t seem to match what I see in pictures of other cribs like it, so I think a few parts might be missing or different.

I know Jenny Lind cribs were made by lots of different companies over the years, so the parts weren’t always the same. I’m just trying to understand what these mattress support parts were usually called and how they were shown in old manuals or diagrams from the late 1970s.

Any general background or old reference info about how these cribs were put together would be helpful. I’m not trying to fix or use a crib — just learn what the parts were called back then.

For general background on Jenny Lind crib styles and how their parts are grouped by manufacturer, this may help:
Jenny Lind baby crib overview