Original vent window latches were glued to the glass, and prone to popping off. The epoxy used is strong, the same as for gluing the base of a rear-view mirror to a windshield, and sometimes takes a chunk of glass with it when it comes off. This is of course due to excessive pressure being exerted by the latch when closed. My recommendation is if they are latched leave them latched and if they are unlatched leave them unlatched. Note that this latch has no screws fixing it to the side vent frame.