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The small board is off of a tape drive and has IDE pins, the sun cpu is obviously not the same as the sun one on the price list because it’s ceramic like an amd k6. The other two I’m not sure about. Maybe high telecom and maybe low telecom

From top to bottom. I will number them with the base 10 numbering system. Octal would be cool but lets not go there.
Board 1 The IDE connector I believe allows that board into High Grade Non-Sata.
Board 2 The Sun CPU. Go AMD Ceramic Aluminum Top/K6. It's a tough evaluation for me. But using the process of elimination. I can't see it any other way.
Board 3 Remove all those mini transformers labeled UMEC. Technically they are junk. I'll say High Telecom.
Board 4 High Telecom. Just looks good with ICs and all the gold pads and gold border.
Board 5 High Peripheral. Why? Those components with the BEL 0443lfa are transformers. If another forum member kicks that into Low Telecom. I will considered myself kicked. And say thank you.
As a personal note on your post. Labeling boards Front and back. 1 or 2. A or B. Is acceptable.
Here to learn like everybody else.
My evaluations are my own.