This is an Olympic version of FED 4b, also known as 4L (for 61 L/D lens).
With the last version of the black cover with horizontal and vertical stripes.
Known serial number range (please extend the range with your serials):
7-digit serial number on the backside of the top:
#???????(owner/source) to #???????(owner/source)
6-digit serial number on the bottom plate of the back door:
#068981(sovietcams.com) to #101094(fotoua.com)
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