7.65mm is the diameter of the bullet, 23 is the length of the cartridge (Casing only)
If they say Length of the revolver, they mean its length in its entirety inclusive of the barrel. The length of the barrel will probably be listed separately.
Lots of nonsense going around about showing empties to shopkeepers... apparently some states/districts have this procedure in effect. Most seem to have ignored it because of the futility of the exercise.
He who can not think, is a fool; he who will not, a bigot; he who dare not - a slave!