No. First, assault occurs when you point the gun at a person (even if you do not intend to shoot... even if the gun cannot shoot... even if it's a toy with the orange safety cap taken off). Since open carry and this is a clear case of Castle Doctrine (defending your home/shop/your stuff) and not Stand Your Ground (Stand your ground does not obligate you to attempt to flee an aggressor against you, provided you have a legal right to be where you are currently standing) and you are well within the right to display the weapon while asking the person to politely leave.
This is less so on an open street, but again, as open carry is in effect and the man is clearly the instigator of aggression, this still falls under Stand Your Ground. This could also be Castle Doctrine if the threatening individual is reasonably likely to cross onto your property, though it's advisable to keep your distance. There is a sub-optimal distance where the outcome of a gun verses some form of melee becomes likely and it's not as close as you would think (I cannot find the distance at this moment).