Germany 9n68 Postcard Help

I do not collect Germany ( am a US revenue collector) but recently was passed down my grandfathers/fathers german collection and have begun the long road of organizing it. I came across this postcard of 9N68 which was issued on October 1, 1950.

Is this a first day cancel for this stamp?
Can I assume this is a legit usage for this stamp?
Lastly can anyone translate what the postcard has written on the back?

Thank you for your time and any help.
Respectfully,
Richard

In my view is a legitime use, as it's a 1950 Berlin stamp , being used there in October 1950.
But I don't know if it's an FDC. "ERP" stands for European Recovery Program, better known as Marshall Plan. It might well be, as the PC shows Gen. Marshall's house.

This is Mi# 71.Yes, this is a legit usage, but no FDC. As you found out stamp was issued 1. oct. 1950.
German catalogues list `amtliche` FDC-s (local FDC).
For modern Germany (1945 onward) I use an older 1995 DNK catalogue, prices in DM- ** 250, * 100, used 100 and `amtl.` FDC 350 DM.
This is a nice find.
Probably there are first day cancellations too, the Industrial Expo was held between 1-15 october 1950, this is dated 13.10.1950
The text:
Dear Lothar, from the Industrial Expo I send you and Ruth-Harriet best wishes.
with (in?) love, your Lieselotte.

Thank you 2 for your help and guidance. I appreciate the knowledge.

Richard