Was there ever a Glock that did not fall into that generation cat.?I have owned a plenty but up until I found AR15 years ago I did not know Glock went by generations for productions.

Sorry for being a post whore... My Cowboys lost tonight... Beer... Wife got a headache (RedSkins fan and I got her a jersey) I guess I will post...

Glock has not officially recognized "Generations" until recently. It was an enthusiast coined classification.

Yes there have been if you define generations by specific features. Like most products that have evolved during production the Glocks have had transitional models. Examples that come to mind are finger grooves with no light rail, 2 pin guns with rails and grooves, and the RTF guns. Those are the most obvious but there have been internal changes as well over the years as far as internals and other things such as different extractors etc.

Gen 1- Only Glock 17's and approx 800 Glock 19's were made.  There's the pebble texture completely around the grip.  IMO, Glock had it right the first time!

Gen 2- Checkering added to the front and backstraps, with the pebble texture retained on the side panels.

Gen 2.5- Addition of the finger grooves, but no equipment rail.

Gen 3- Finger grooves with the addition of the equipment rail.  It is early during this time that Glock transitioned to a 2 pin frame on their 9mm models to standardize their frames.  I believe that occurred around Sept or Oct of 1998.

Gen 4- What you see now.

Those are the main "generations", although there are a few minor engineering changes during these times.