A few years ago, a guy at my PD retired and turned in his issued gun, an ancient 1st Gen G17. It even had ancient mags that came with the gun. None of the three were locking the slide back. I tried telling the Chief that mags were consumables and we should just buy 3 more but he insisted I sent them back to Glock. I did, along with a letter asking them to check them out for function. A couple weeks later, we got 3 brand new G17 mags in the mail to replace the 3 old ones. I haven't had very good luck with Glock's customer service but, for LE anyway, they will exchange old mags for new.
Bub75