mono cartridge vs stereo

With a lot of mono reissue (hence in RIAA eq), beside mono cartridge, will it be beneficial to use dedicated mono phono preamp? There is one offered by Oswald Mill at $1500 and rated A by Art Dudley, wondering if it can give significant sonic improvement on mono reissue.

Thanks Lewm, finally someone has shed some lights :)
Just realized, unless I missread, when somebody shared their experience with mono phono preamp (Art Dudley in Stereophile and Jacob H in absolute sound online), they didn't mention whether they listened to 2 speakers or just one.
Do you have any experience listening to mono phono preamp via 2 speakers vs 1 speaker?