The rear sight is also consistent with the Egyptian contract. The rear sights on the Argie and Dane were both drastically different. The chambering should be .43 Egyptian.
It would be a good idea to have it checked out by someone who knows RB rifles, before shooting it. Perhaps someone who knows the mechanics will chime in re how to determine whether the breechblock and action are within spec for shooting. If you don't get a response here, you may also want to post on the gunboards, surplusrifle, or mausercentral forums. They get a bit more traffic and focus more on the old stuff.
Your rifle was probably purchased from Sarco in the 1970s, already modded into a lamp. They had a bunch of beater Egyptian RB's, back then, that weren't selling very well. That said, yours seems salvageable if the bore is OK. The quality of manufacture was quite high on these rifles. The action can likely be repaired if the breechblock is too loose in its present condition.
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