1. Experience has shown that overhauling the distributor makes no sense, even if spare parts for it are available for sale. Typically, the distributor cap, rotor, breaker contacts, and capacitor require inspection. Apart from these, there are no parts in the distributor that wear out significantly (except for the roller and centrifugal regulator). If at least one of the mentioned parts is so badly worn that it needs to be replaced, it can be assumed that the others are also worn, and it is better to replace the entire distributor assembly. For those who decide to rebuild the distributor, Figures 4.b and 4.7 show disassembled versions of the two types of distributors used on the Peugeot 305. Rebuilding shouldn't be a problem, provided you memorize the exact position of all parts, even the smallest ones.
2. The assembly sequence of the Ducellier distributor is shown in the attached photographs.