You keep going back to the tooling up issue...the hardest part of setting up a manufacturing base is actually tool making. Depending on the timeline, and based on their experience in 1948 making Armored Cars they would have simplified. This is quite normal process. Also the Panther type suspension was way over engineered, except for the French Prototypes it was largely dropped post war. By the time they would have been manufacturing the 1950's the French already had the M47 Tank, and would have shared their information with Israel and they would have used a simpler to manufacturer torso bar set up. Also they would have changed the Transmission.
Just having the drawings doesn't mean that its easier to build. Having worked over twenty years in manufacturing as a designer/draftsman. It is based on what you have to build your tooling.
Having worked 35 years in design and manufacturing I know exactly what you mean, but if you have to design all the tooling, including some (just some) that is a bit more complex) for a complete design you have versus holding up tooling the stuff you have to wait until you go through the design and development phase for a new and significant portion of the system and then tool it all up, it's going to take longer and cost a lot more.
But, hey, that's my take based on my years being a design and project engineer in three industries. If that's not your take, we can agree to disagree, because, lets face it, they didn't do any of this in real life and we're spitballing here. :-)