I think that's right. I found some envelopes at work with design documents for similar looking boards, and that's how they were made. Drawn on paper, laid out o

I think that's right. I found some envelopes at work with design documents for similar looking boards, and that's how they were made. Drawn on paper, laid out on clear film with tape and adhesive transfer pads, and photographically reduced for etching. One of the envelopes even includes a roll of punched paper tape, which I assume is the drill NC program. I've since re-created the boards in KiCAD, but I hung onto the old documents because they're such neat historical artifacts.