Maybe I'm wrong but the coating on the ms9 29t tube appear different from the common ms9 29A and S. And yes the tubes are basically all the same , maybe Taito personalized this one with a more aggressive coating.
The chassis are also the same, the 29t not have two film caps near the ntc and add a shielding plate under sync ic.
On Egret 2 they made a special wiring to autodegauss which can only shorten the life of the PTC because the degauss circuit just run hotter, most likely I will wire a manual degauss button and remove this coating.