Hussein,
Coincidentally, I digged today through SIPRI arms trade database, doing research about my country's Army procurements during Cold War.
Now, while Wikipedia doesn't mention Bulgaria as receiver of this weapon type,Bulgaria bought 2 varieties of Frog:Luna/Frog and Luna-M/Frog-7.I've seen a Frog on tracked vehicle in a military museum in Lovetch recently:

It seems to me, that SIPRI uses the designation Frog for the early-carried on tracked vehicle missile system, while for the later-based on ZIL-135 truck, SIPRI uses Frog-7.
I've checked the record for Artillery deliveries in Egypt and there is a record of 12 launchers Luna/Frog, ordered in 1965 and delivered to Egypt in 1967.These should have been carried on 2P16 tracked vehicle-like the one in Lovetch pictured above.
12 Luna M/Frog-7(the ZIL-135 based modernisation) were ordered from Egypt in 1968 and were delivered between 1971 and 1972.
Hope this helps!