There is only one RIAA curve, yes, only one. That standard inverse RIAA curve EQ is built into every phono input, and all LPs are recorded with the RIAA curve. Stop talking absolute nonsense that comes from your "you know where". LPs since 1948 have been recorded with the RIAA curve. In the 78 era different companies had different curves, and the forcing of the RIAA curve ended that confusion.
So, you can see that if you did not use the RIAA EQ on playback there would be a massive HF pre-emphasis and the disc would be unlistenable.
Cassette tapes all have a similar system based on the tape formulation. There are tabs on the back of the cassette that selects the correct EQ when you insert the tape.
Reel to reel unfortunately had three CCIR, NAB and IEC for each of the three had an Eq for all of the playback speeds. Without that disc noise and tape hiss would make the program unlistenable. This is apart from Dolby/dbx etc. which where dynamic Eq varied according the moment by moment dynamic modulation. HF boost was higher in quieter passages and less in louder passages. Now you have had your lesson for the day.