the early Apple lasers ARE Hp lasers, they are the same as the hp LJ II and III series, same parts in most cases. I used to do minor service to hp II III and the apple ones (apple laserwriters? maybe that was thier name) at my first IT job.
I owned the original HP laserjet, it had a funny model number even though it was the first,, and it only had serial communication. Big units, real workhorses, they would still run fine today if you had one. Only drawback was 300dpi up until the hp LJ4 series.
I didnt mind, I had an HP Lj IIP because it was smaller for years, sad I gave it away.
Wells they have logic boards, they have RAM. They have IO and expansion bays. I think they were RISC based. I dont know what you would do with them. modern laserjets have far more advanced computer systems in them. Ill agree they were smarter than dot matrix or daisy wheels of the time.