I have a few Glock OEM magazines for sale that I got in a lot purchase.   All the mags are in excellent condition and some appear to never have been used.

G17 9mm 17 rd    Gen 4, Notch for Original, Ambi and Reversible Mag Catch   (3)  $19 each or $55 for all three.

G21  45acp  13 rd   Gen 3, Notch for Original and Abi Mag Catch,  (1)   $15