All:
I was doing a little regular maintenance tonight. I had two EGs out at the same time. Both in 300. One was pre war (lighter colored one) and the other a post war 50s model. Anyways, I noticed some differences between the two.
One, was the thickness of the forearms. The pre war gun was much thinner.
Second, the shape of the shell indicator hole. The pre war gun was more circular than the post war.
Post war
Pre war