No, you remember wrong, 5:4 was extremely uncommon, 1280x1024 is the only 5:4 resolution I have ever seen in the wild, compared to 320x240, 640x480, 800x600 and 1024x768.
(Does anyone else fondly remember the short moment in time when all laptops and all projectors had 1024x768 as their native resolution and you could expect presentations to just work?)