STAR Bonifacio Echeverria, S.A. .380 cal and yes it is the first D model , circa 1927 looking at the proof marks.
TenX,
You almost got it right , I thought you would have guessed the right caliber when I told you that the frame was not alloy and of course the fat .380 bullet was kept especially as a hint

The reason why I posted the pics was that I had never seen a Star .380 pistol as compact as this before, I have been given to understand that this is a rather uncommon piece.
best,
RP.