1886 10 Cent Is This Obv. 4 ?

Well worn coin,appears to have the flat forehead of OBV5

The leaf and/or the the legends have nothing to with differentiating the obverses.
There is no leaf on the obverse.
The legends are unchanged between obv4 and obv5, no completely new matrix was made, only the portrait was modified.

It is Obverse 5. There is a simple trick to distinguish the two. On a photo, mark a line from the tip of the lower leaf at the top of the head to the tip of the nose, continuing to the "C" in VICTORIA and the denticle. This line will almost parallel the forehead on Obverse 5, but have a large forehead bump protruding to the left of the line on Obverse 4. Here is your photo with the marking line.

The bulge on Obverse 4 is much larger. Below is a closeup of an Obverse 4 that is marked.

There are many other markers, as well. The tip of the second leaf at the top of the head is more rounded on Obverse 4, and more pointed on Obverse 5. The top knot on Obverse 4 has a slightly pointed tuft of hair directly below the second "A" in GRATIA on Obverse 4, but is more flattened on Obverse 5. The points at front and back truncation of the neck are more rounded on Obverse 4 than on obverse 5. The neck is wider on Obverse 4 than on Obverse 5. All of these are still visible on heavily worn coins, which is what makes them useful as markers.