Morning Winmag - agree with the ‘not dwelling on Made in China’. Still if it works.... The mag carrier looks like it would hold the 20 round as well. Who makes those magazines? Magpull?
The two magazines shown are Lancer and H&K. Magpul would also work, but you have to leave off the top cover. The Magpul also has a "fat floorplate", so you can only insert the bullet end.
Just about any M16 mag, including a 20-rounder, will work, one way or the other.