states table:

    {SPR_SHTG,4,0,{A_Light0},S_NULL,0,0},       // S_LIGHTDONE

->

01 00 00 00  04 00 00 00  00 00 00 00  ?? ?? ?? ??  00 00 00 00 
00 00 00 00  00 00 00 00

starts at 0009f3cc in doom2.exe
starts at 0009f0c0 in chex.exe

mobjinfo table:

    { -1, S_PLAY, 100, S_PLAY_RUN1, sfx_None, 0, sfx_None, S_PLAY_PAIN,
        255, sfx_plpain, S_NULL, S_PLAY_ATK1, S_PLAY_DIE1, S_PLAY_XDIE1,
        sfx_pldeth, 0, 16*FRACUNIT, 56*FRACUNIT, 100, 0, sfx_None,
        MF_SOLID|MF_SHOOTABLE|MF_DROPOFF|MF_PICKUP|MF_NOTDMATCH,
        S_NULL },

ff ff ff ff 95 00 00 00 64 00 00 00 ...

starts at 000a5d90 in doom2.exe
starts at 000a5a84 in chex.exe

state differences:

  state 537: tics reduced from 8 -> 3
  state 538: tics reduced from 8 -> 3
  state 539: tics reduced from 8 -> 0
      faster boss firing rate?

mobjinfo differences:

  mobj 1 : fields 11 and 12 swapped (0, 184) -> (184, 0)
  mobj 2 : fields 11 and 12 swapped (0, 217) -> (217, 0)
     these are swappings of meleestate and missilestate (flemoids only
      attack at close range?)

  mobj 15: fields 17 and 18 changed: (1572864,4194304) -> (2883584,6553600)
     wider and taller - boss?

  mobj 18: field 12 changed (589 -> 0)
     far attack frame set to S_NULL - lost souls don't do the charge attack