What alternator do I have?

[enine]

I'm cornfused here. Chevy's web site says the Z71 package includes a 145A but I have RPO code K68 which says 105A. The pics in the how an alternator works are not working. Anyone that can tell me for sure?

[HAZARDOUS1500]

i always thought that the 145's were optional and the 105's came stock. if you have the window sticker it will probably say.

[enine]

I don't have the window sticker, I bought it just a bit used. Usually the 145's are optional, but Chevy's website says with the z71 option the 145 is included in it. Maybe they get the K68 by default unless you order the 145A without any other option package such as the z71 so the z71 overrides it, but if you didn't get the z71 then the k68 gets replaced by the code for the 145A. Thats going to be my best guess. I think I'll sell my 90A isolator and get a bigger one just to be safe.