Parts Are modified and upgraded over time. I expect the refurb Glocks have the newest parts installed.
The guy who said you can't improve on perfection was wrong. He must have been a 1911 guy.
Actually, it was Gaston who said that. The guy who founded Ghost Inc went to Gaston Glock first and was told you can't improve upon perfection. He ended up founded Ghost independently.
"If our lives are endangered by plots or violence or armed robbers or enemies then every method of protecting ourselves is morally right" -- Cicero
"Governor, I haven't let another man touch my gun since 1861."