Code P0300 and P1195
 

Hi ,
I havea Mazda protege 96 model and recently I went for a state inspection . Kwik car guys gave me the code P0300 and I got that fixed at firestone . Now when I again took the car for state inspection they told me that the code P1195 is coming now . I surfed over the net for these codes and got to know about them.
My question is : Is there any chance thatthese codes are interelated ? Like while working on the code P0300 firestone guys might accidently induced the code P1195 which relates to the EGR valve.
Another question is if these codes were originally present in the car then during state inspection why 1195 didn't come up ? Is that the machine can't detect the code 1195 if P0300 was present .
Will appreciate if somebody post the reply ASAP.