The blocks you are showing are nothing special. The design is showing it’s age.
Do you feel the need to try and find something of a specific vintage or OEM structure?
IF not, then there are many options.
Spinnakers are often handled with free wheeling blocks.
You can find a plain block from Garhauer Marine, Harken, Lewmar, Ronstan that will serve your purpose. It looks like you have a fixture attached to the block. It could be replaced by a strong padeye that could fold down to keep it out of the way. When not in use. The pad eye could be put to multiple uses not just for spinnaker blocks that may rarely get used.
Here is an example of Garhauer Marine’s aged block from eBay.
A folding Pad-eye…

Attachment can be several ways. I prefer a soft shackle for my spinnaker blocks. Attached to the pad-eye.