In my book, he has a personal agenda and very strong bias in his presentation of selective information, when it relates to conflicts between a Muslim army and anyone else.
Extremely so when the opponent happens to be those (Damn J..) Evil Zionists. But YMMV. Make your own opinion.
(Anyway, it's not a topic for this section of the forum)
Indeed, it is documented that some Mirage 5J / Nesher kits came more-or-less clandestinely among spares shipments from Bordeaux-Merignac. At least one Nesher on display had a manufacturer plate showing so.
Now how many kits, a single one as IAI says, or many more? As Archibald wrote, there are conflicting versions. Let's just keep in mind that in this time Mirage 5s were in full production for Arab countries, Israeli-designed improvements included. Libya received 85, and transferred some to Egypt, then the direct opponent. Oh well. Nations, friends, intererests...
As we know, a few years later IAI was manufacturing whole new-build planes, the KFIRs (a further development of the 5 with canards and a J79). Most likely there was a ramp-up from the first kit assembly, but the details are not public.
Again, everyone can make their own opinion.
Let's go back to prototypes and projects.
