Hiya Woodsyi
I got to searching and came up with this......
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Equalization Curves by Name
Turnover Rolloff
AES 400 Hz (375) -12 dB
FFRR (1949) 250 Hz -5 dB
FFRR (1951) 300 Hz (250) -14 dB
FFRR (1953) 450 Hz (500) -11 dB (-8.5)
LP/COL 500 Hz* -16 dB
NAB 500 Hz -16 dB
Orthophonic (RCA) 500 Hz -11 dB (-8.5)
629 629 Hz (750)
RIAA 500 Hz** -13.7 dB
* modified from NAB: less bass below 150 Hz, requiring about 3dB boost with bass tone control.
** "Very close" to NAB.
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Equalization Chart for Pre-1955 LP Records
Turnover Rolloff
Angel NAB -12 dB
Audio Fidelity NAB -16 dB
Bach Guild (501-529) NAB -16 dB
Bartok 301-304, 309,
906-920 629 Hz (500) -16 dB
Boston COL -16 dB
Caedmon 1001-1022 629 Hz (500) -16 dB
Capitol AES -12 dB
Capitol-Cetra AES -12 dB
Cetra-Soria COL -16 dB
or AES -12 dB
Colosseum AES -12 dB
or COL -16 dB
Columbia COL -16 dB
Concert Hall AES -12 dB
or COL -16 dB
or (until 1954) RIAA -8.5 dB
Decca AES -12 dB
Decca (until 11/55) COL -16 dB
Decca FFRR (1951) 300 Hz (250) -14 dB
Decca FFRR (1953) 450 Hz (500) -11 dB (-8.5)
Ducretet-Thomson 450 Hz (500) -11 dB (-8.5)
EMS 375 Hz -12 dB
Epic (until 1954) COL -16 dB
Esoteric AES -12 dB
Folkways COL -16 dB
Haydn Society COL -16 dB
HMV COL -16 dB
London (up to LL-846) 450 Hz (500) -11 dB (-8.5)
London International 450 Hz (500) -11 dB (-8.5)
Lyrichord COL -16 dB
or AES -16 dB
new: 629 Hz (750) -16 dB
Mercury (until 10/54) AES -12 dB
MGM NAB -12 dB
Oceanic COL -16 dB
Oiseau-Lyre (until 1954) COL -8.5 dB
Overtone NAB -16 dB
Polymusic NAB -16 dB
RCA Victor (until 8/52) NAB -12 dB
Remington NAB -16 dB
Urania (most) COL -16 dB
Urania (AES eq) AES -12 dB
Vanguard (411-22, 6000-18) COL -16 dB
Vox (until 1954) COL -16 dB
Westminster (before 1956) NAB -16 dB
or AES -12 dB
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Looks like I remembered wrong. It seems they all adorted RIAA in 1955 rather than 58.
I'm pretty sure the Hagerman makes the phono EQ you are looking for in kit form. You might be able to take your existing Bugle and add a selector switch to add a few of the EQ curves above. If I do some more digging, I might be able to come up with a schematic if you want to try the switch.