Solidworks save format question

Hello, 

My client asked me about save format can be set in Solidworks.

When saving an assembly, is there a function that allows the default value of the file format to be *.sldasm. Current default seeting is *.sldprt.  

(Or, when saving an assembly, ask if there is a function to hide or remove the option to save as *.sldprt.)

Thank you in advance.