"Users of wide-range playback equipment should compensate for the RIAA curve"

My Uncle Johnny’s Fisher ’President II’ console (which I inherited), made in 1958 while standards were being resolved, had a few options. Live Binaural Radio existed for a very brief period. You tuned CBS FM, then tuned CBS AM, then snapped to ’Stereo Radio’

https://www.audiogon.com/systems/11420

I am not one to fiddle with adjustments and options, but, I've played with phono stages that had different equalization curves.  Even with modern records that were mastered with RIAA equalization, sometimes a different equalization sounds better.  Some phono stages even offer infinitely variable equalization--you can change both the crossover point on a continuously variable scale, and the slope of curve, also on a continuously variable scale (FM Acoustics offers this).  I would probably go nuts if I had that kind of choices.

I’m certain they’re telling you to specifically use RIAA phono equalization - which is of course the defaut for virtually all phono stages, now. But I agree the choice of wording was poor. If they were using ANY other curve to cut that record, they would have mentioned it by name. 

Even with the correct EQ, older records can sometimes tend towards sharp / bright treble. The playback components of those days weren’t treble / HF assault-cannons like a lot of hifi gear is now - they were usually mixing for softer, much more laid back speakers (e.g. paper cone tweeters). 

Hagerman makes a reaonably priced "Achiver" phono stage, with widely adjustable Turnover & Cut knobs for totally custom phono EQ dialing. Not sure I’ll ever have enough records that would need it, though. The other alternative would be something like a Schiit Loki, for a fully adjustable analog EQ - it’s not a phono EQ, but might be better for overall fine tuning (e.g. softening sharp treble). Or (god forbid) digital EQ :) 

…,Some phono stages even offer infinitely variable equalization…

Very satisfied with my VDH current phono.  Maybe someday I’ll check out variable RIAA phonos, but other audio components tugging my limited budget.  

What cleeds said. Seems like the 2022 re-issue is simply recreating the language that was on the original 1956 cover. By the way, the Bethlehem mono LPs I own are typically fantastic, mostly Japanese reissues earlier than 2022. Same goes for stereo LPs from Bethlehem.