Allegro 1500 Special (HL) in France

Hi, sorry for my bad english, I'm french.
It's a project that I have at heart, my father owned one in the 80s.
I just bought a 1977 Allegro 1500 "Special" (french denomination for "HL") in rust-free condition.
It was kept for years surrounded by hay bales in a barn. That's probably why it's not rusty.
The car is overall complete. In addition, I have a few parts in advance of another model (a 1300) that we couldn't save.
However, the mechanics are not the same, so I don't know if everything will be compatible. For example, I have a driveshaft to replace, I don't know if it's the same on the 1500 and 1300 models. If anyone can tell me if there is a difference, I thank them for that.
I will also need to do a good mechanical overhaul, so I will need parts that I would have trouble finding in France, if you know addresses, please let me know.
I will keep you informed of the steps taken to get this car back on the road, which is unloved in my country (however french people generally have bad taste, as evidenced by the fact that they buy Renaults), but which I consider very interesting.