I want to know whether the open laszlo mouse down events will be converted to touch events while compiling it in mobile format.
Yes, at least on iPad. I tested this myself on an iPad2 running the OpenLaszlo 4.9.0 in HTML5 (aka DHTML) mode of my application last year for R&D purposes and the following were confirmed to work:
1) Touching a button on the screen in the application in OpenLaszlo HTML5 mode properly triggered the onclick event of the button.
2) Drag and drop with your finger on a touch screen in OpenLaszlo HTML5 mode has the same result as dragging and dropping with the mouse on a non-touch screen system.
Note: This was only tested on the iPad2, it was not tested on Android, Windows Phone, Blackberry, etc.