Quality grease gun ?
No idea, anymore. Used to be Lincoln/ Alemite, you might look at garage/ estate/ Ebay sales for a good old used one.
I "would not bet" that NAPA is decent quality anymore, their replacement auto parts (when you can get them) sure as hell aren't.
There are 3 or 4 women work at O'Really's any one of them are more helpful than the people currently at the local NAPA