Gen 4 will usually say Gen 4 on the slide. Gen 4 also has a much larger mag release and uses the larger guide rod, as well as having the removable backstraps. Gen 5 deleted the finger grooves, similar to a gen 2. And Gen 2 would have no finger grooves but also would not have the rail for a weapon light.
No, the 19x frame is shorter than a 17.
No, the Gen 3 Model will require this kit:
https://www.opticsplanet.com/advantage-arms-glock-17-22-22-lr-conversion-kit-w-10-round-magazine-and-range-ba.html
Yes, the magazine loader is included with the conversion kits.
Yes, the Gen 4 Glock 34 can use the Gen 4 Glock 17 conversion kit.
Yes, the Glock 34 Gen 4 model will use the Glock 17 Gen 4 conversion kit.
Yes, extra magazines can be found here:
https://www.opticsplanet.com/advantage-arms-glock-17-22-gen4-22-lr-conversion-kit-w-10-round-magazine-and-ran.html
Yes, extra magazines can be found here:
https://www.opticsplanet.com/advantage-arms-glock-17-22-gen4-22-lr-conversion-kit-w-10-round-magazine-and-ran.html
No, the Gen 5 model requires the Gen 5 specific conversion kit found here:
https://www.opticsplanet.com/advantage-arms-glock-22-long-rifle-conversion-kit-w-10-round-magazine.html
We do not currently carry this conversion kit with a threaded barrel.