The A10 & the A12 from the Datsun 1200 car had the distributor on the same side as the later A12's, A14's etc, but it was mounted up towards the front of the engine. These engines had the altenator mounted low on the left, or manofold side of the engine.

When the engine was redesigned to allow air conditioning compressor mounting, the altenator was moved to the place previously occupied by the distributor. This meant that the Distributor, the fuel pump & the engine mount on that side were all repositioned further back to allow for the altenators new mounting.

ALL "A" series Datsun engines have the distributor on the same side, but some are to the front, & later ones are much further back.
Chris