The manual for my '79 100hp says when removing the air silencer base to get to the carbs (for a carb clean/re-build) to discard the air silencer base mounting screws and to use new screws when reassembling....I'm assuming since the manual says to replace with new screws that it must be of some importance so my question is should I order the specific screws from the motor's parts list or can buy the same size screw in a similar grade/material from a hardware store?