Zev only lists Gen 3 and Gen 4 Glocks for fitment, but I do not see any reason these would not fit the Gen 5 magazines as well as the magazines have not really changed from Gen 4 to Gen 5.
Zev does not currently offer an extended base mag for Glock 19. Here is a link to an alternative:
https://www.opticsplanet.com/taran-tactical-innovations-19-23-4-5-firepower-base-pad.html
According to the manufacturer the ZEV Technologies Glock Magazine Basepad does not work with 10 round magazines.
The ZEV Technologies Glock Magazine Basepads are made of aluminum and these fits standard capacity Glock 9mm & .40 magazines but will not fit 10 round magazines.
Glock magazines have not changed much over the generations. This should fit into a polymer80 frame as well.
Yes it should, it should fit any Gen 3 or 4 OEM Glock magazine that is not capacity limited.
Updated answer: Yes, this would fit gen 5 Magazines.
ZEV only guarantees that these will work on OEM Glock magazines. It's possible they could work on aftermarket magazines, but it would depend on how close they are to factory magazines.
Yes, it will work with standard capacity Glock 19 magazines (15 rds), it will not work with reduced capacity 10 round magazines for Glock 19.
Yes, it will work with standard capacity Glock magazines, it will not work with reduced capacity 10 round magazines.