I typically give a new gun a once over clean, make sure it is nominally lubed. FWIW the last two used Glocks I bought still had the copper lube on them. The G17 was hard to tell if it had ever been fired and the G26 had been fired some and had a little bubba sanding job on the grip under the trigger guard but it actually fits me well.
I figure if you lube it enough to have to wipe it off after a handful of hand cycles and then no more comes out I am OK. But I have been wrong before.