I just yesterday downloaded the mame2003plus brick. 🙂
And I have 0 experience with it. So give it some time please, perhaps somewhere in 2019 possible for cleanup. My own experience within other mame sets is, that very often you find some in the wrong deposit, or just not working or a mixup between zip part and chd's. Not so evident. If you give us some time, we will knew more later after.
There are some speciality's anyway inside, like the taito games, mirrored from origine. This arcade cabinets where constructed with mirrors, and there is no dip switch mode to revert this.
So, as for now, I use a shader "flip-horizontal.glsl" for the job, as not gun/mouse axis also inverted.
But I have another problem for the moment. In Recalbox for mame2003, if you choose in retroarch game cfg override or core cfg override, he memorize a file in /.config/retroarch/config/mame2003/ as mame2003.cfg for core override and name_of_game.cfg for game override. This seems to be different in Batocera.
So, all this takes time ands I would stay it for the moment. With 2016, the 174 core is not the first choice, better to replace (for the moment) by 180 or 181.