Next to nothing on the board itself but the connectors seem to have quite a bit of gold. Thoughts?

I highly doubt that will be accepted as Backplane. This is what I do with PCBs like that. I remove all the connectors. Check that each one has gold contacts. Then submit them as Connector Ends. That gets the job done for me. There probably are other opinions about that board. Possibly the whole board could go Connector Ends. I haven't tried a submission like that yet. Then again. It is only Low Grade. Your question concerning that board is sort of a Rubik's Cube type question. For me anyway. So. I just depopulate the connectors and submit as Connector Ends. It works for me. Gets it done.
Here to learn like everybody else.

It's similar to but not a typical backplane and I agree I don't think there's enough there for backplane. I would probably put this in low peripheral as is.

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Here to learn more so I can recycle more
My grades are my own opinion and not an official grade from Boardsort

Cool. Low Peripheral.
Here to learn like everybody else.

Low peripheral makes sense. Thank you