Tobruk Overprints On Later Reich Stamps

Afternoon all,
Noticed today on ebay a seller with several late issue German Third Reich stamps for sale, all carrying an overprint that read 'Tobruk 21.6.42' with an eagle over swastika emblem. I was curious as to why (if at all) the German postal system would issue an overprint which obviously commemorates their victory at Tobruk much later than the event. The stamp I noticed this on was issued in January 1945, when the war was taking a bad turn for the Germans. I asked the seller what he knew about the overprint, but he simply said he was 'not an expert'. Does anyone know if this was a genuine overprint?
Thanks in advance.
DavidR

No such stamps existed 10 years ago ,I seen a major exhibit of the postal history of the AFRIFA-CORP. {SP} back then and there was nothing like that in the exhibit .Most likey a computer made overprint .Old story take a 5 cent stamp, overprint it and then get $2.00 for it on ebay .

Thanks floortrader, that's what I thought too, the dates made no sense. But the guy is selling them nonetheless.

I've noticed a large number of fantasy or otherwise bogus overprints on ebay the past few years, mostly, it seems, from sellers in Greece.