I recently purchaced a generation 3 glock 22C (with rails and thumbrest) with serial # ECPxxxUS the serial number checked out to be made in 1993 but my local gunshop insists that the gun coludn't be this old. I also thought the generation three and the compensated barrels were new features. Does anyone know the year of manufacture of this gun and if the US at the end of the serial has any significance. The gun has no signs of wear except for the side-peening of the slide. Also the magazine checked out to be made in 94, I believe this because it is marked for mil/leo.

According to this site, it was manufactured in 5/1993.  The G22 came out in 1990, so that date sounds reasonable.  The third generation Glocks have been out for quite some time now, though I can't give you an exact timeline.  They sort of "evolved" from one generation to the next.  Some models are even considered in between generations.  Such as a generation 2.5.  You can probably find out much more information over at Glocktalk.com.

The US simply means the gun was imported into the US by Glock.

Quoted: I recently purchased a generation 3 Glock 22C (with rails and thumbrest)with serial # ECPxxxUS the serial number checked out to be made in 1993

If all the serial numbers match the G22 was made after 1998(when the 3rd gen was introduced).

Quoted: I also thought the generation three and the compensated barrels were new features.

The G22"C" was introduced in 1998 also.

Quoted: Does anyone know the year of manufacture of this gun and if the US at the end of the serial has any significance.

BATF required all firearms to have at least 6 numbers and/or characters. Glock started with AAxxx and added "US" to meet the requirement. The "US" was dropped in 2000 IIRC.

Quoted: Also the magazine checked out to be made in 94, I believe this because it is marked for mil/leo.

All standard capacity mags(11rds or more) were stamped "LE" only and dated Sept.14,1994 during the AWB. When it expired so did the need for stamped mags. It does not mean you mag was made in '94 just that it was made during the ban, so it could have been made as late as Sept 13, 2004.


So my guess(without calling Glock) would be yours was made between '98-2000.

Quoted: According to this site, it was manufactured in 5/1993.  The G22 came out in 1990, so that date sounds reasonable.  The third generation Glocks have been out for quite some time now, though I can't give you an exact timeline.  They sort of "evolved" from one generation to the next.  Some models are even considered in between generations.  Such as a generation 2.5.  You can probably find out much more information over at Glocktalk.com. The US simply means the gun was imported into the US by Glock.

in that site I can't find my glock (glock17 GNRxxx)

All numbers match. Seems to be a good. The price was decent also it has trijicons, and a lasermax for $500. I guess the website lookup is wrong. It doesn't even have my 19 with serial HKK on it.
Is the side peening an issue that needs to be addressed. Will it affect reliability. Is there anything that can be done to fix the wear.
I have yet to shoot the gun but my father loves it he says it doesen't hardly kick any. His first shot was bullseye at 15 yds.

The serial number lists at TopGlock and at Glock Talk are far from complete.  My 2nd gen G22 is on one list and not the other and the used G26 I bought a few months ago isn't on either.  When in doubt call Glock.  Personally, if all the numbers match I wouldn't worry about it.

Quoted: Is the side peening an issue that needs to be addressed.

No, it will only progress so far then stop.

Quoted: Will it affect reliability.

No

Quoted: Is there anything that can be done to fix the wear.

You can totally eliminate slide peening by changing the recoil spring & guide rod to a #20 spring.

I have a stack of DEP prefixed buns, made not too long after yours and they are from 1999 I believe

The "C" models were introduced in 1998 as previously mentioned

I just entered my G19 S# that I know was made in '03 and it says it was made in 6 1989 so I'm not so sure how accurate that site is

That site isn't right.

ASKxxxUS, Gen 2 Glock 17, purchased in Feb 1994.  The site said 01/1900?
FZxxxxUS, Gen 3 Glock 17, purchased in Nov 2003.  The site said  05/1989?

Here is a thread on glock talk that has a listing of serial numbers and there info.  
Glock talk link

If your number isn't there you can look before and after it(alphabetic order) and get an idea when it was mfg.  

ECP would fall in 2001 somewhere.  EC#### would fall between '87 to '89.  Older sn's only had 2 letters.  They went to 3 letters to start their serial numbers in 1992.