Well, we know that ST-0206004 is Little Taichi now.
Which also means that it was only five games in before Sintax started reusing an engine. Five. (Granted, Donkey Kong 5 was a much more intricate graphical hack than their usual, but still.)
Edit: And something to throw a wrench into the whole "chronological order" thing. Super Robot War X is GT-0210001C. Which means...its sequential ID is earlier...but it came out in a later month than Little Taichi...?
Edit #2: Hm. Maybe the last three digits are still chronological, but the year/month are those of the specific printing? That...sort of makes sense, possibly. I'm almost certain that Super Robot War X is their first game, anyway, as the ROM doesn't have Sintax's typical assortment of tiles left over from previous games.
...Curiouser and curiouser. Guess what's buried in the Little Taichi ROM? Why, leftovers from Harry Potter! No, not the Super Mario DX play-alike, but the one with the Lemmings music.
Clearly, production order is not necessarily equal to release order.