Is there a problem with my friend's CW45?

[BLUEPSTU]

My friend just recently purchased a CW45 and noticed after shooting that there was a little up and down play between the slide assembly and the polymer part of the gun. The gun does seem to draw up or tighten as you fire the gun. When we took it apart, we could see a difference between his CW45 and mine. On his gun, there is no groove/half moon on the underside of the barrel that the guide rod and recoil spring sit. It is just flat across. There is one on my gun. I know the picture is blurry but you can see the groove on my gun. (Mine is on the right and his gun is on the left.) Did Kahr make some of the guns different or is there a problem here? Thanks for any info.
http://i51.photobucket.com/albums/f380/Iceman1266/STA73056_zps7ba16b4a.jpg (http://s51.photobucket.com/user/Iceman1266/media/STA73056_zps7ba16b4a.jpg.html)

[gb6491]

My CW45 barrel is flat across in that area:
http://i43.tinypic.com/2yto4m0.jpg
Regards,
Greg

[BLUEPSTU]

Thanks for the reply, Greg. Hope all is well. I will let him know. I wonder why mine is grooved???

[gb6491]

Thanks for the reply, Greg. Hope all is well. I will let him know. I wonder why mine is grooved???
Life is good, hope it's the same for you.

I don't have any info as to why there is a groove/pocket in one and not the other, perhaps one version is updated/improved or one version cost less to make.
FWIW, my CW45 is around 4 years old (SN: SD39XX)

Regards,
Greg