As far as I see the shoe is not of usual Arsenal production. In 1953 they were to dull with a thick cylindrical stopper (something like 6mm in diameter). It seems that the shoe is original and was modified from the no-number shoe. The engraving was done in Arsenal in 1953 and was filled with black paint (I expect there is no chrome under this paint). Usual shoes from 53 are without the black paint and digits looks like to be stamped and with thicker font.
The history of this camera for me looks like the following: The camera was produced in Dresden and was kept there in warehouses. In 1945 it was sent to Jena. This batch contained the no-number camera I mentioned above. In 46-47 these cameras were equipped with a new front plate and new leatherette on the back door. In 1947 these cameras were sent to Kiev. In Kiev they were kept in warehouse and were forgotten. In 1953 the cameras were discovered and were engraved with the serial number. The no-number camera was discovered much later (perhaps in the beginning of 90-ies, I have indirect proof of it) and was not numbered at all. At least these cameras are from the very early batch of Dresden-Jena Contax-Kievs brought to Kiev.
I expect there are no traces of Contax engraving left on the front plate since the plate was produced in Jena. The number scratched on the shutter housing would be something like xx or xxx if more than hundred such cameras existed. It would be probably scratched rather than engraved. And I don't think that the font would be with no rounded digits as Ulrich assumes.
If you, Jed, remove the front plate please look on any markings. I've found the scratched sign like a window on no-number Kiev.
Jacques M. has found a real jewel of the early Jena Contax story. He planned to post his find on ussrphoto. It is not Soviet camera but is interesting evolution specimen in the history of Kiev migration to USSR. Now I think intrigued everyone enough

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