The Verdict: Unlikely
The law lets the Interior Minister restore nationality lost before 1975, but it is a long shot, with no reported practice for people who left in the 1950s and 1960s. To try, write to the Minister through an Egyptian consulate.
Article 18 of the Egyptian Nationality Law allows restoration for anyone whose nationality was withdrawn, stripped or lost before the law took effect in 1975, with no waiting period. That includes people who lost it under the 1956 nationality law, which stripped Egyptians who left with no intention of returning, along with their wives and minor children. It is entirely discretionary.
Article 1 of the current law still excludes anyone it describes as a Zionist from its provisions on who is Egyptian, and that exclusion has not been repealed.
Restoration benefits only you, not your descendants. Send whatever proof of former Egyptian nationality you hold: an old passport, a birth certificate, or a copy of the decision that ended it.