Classic/Antique Car Repair: VW engine block #, hp engine, sequence number

Question
I have the stamped engine block # of my VW engine,but have no idea what make and model it is. I need the make and model # to order replacement parts. Could you help me? The # is:
D 106 3831

Answer
According to my book, the "D" would indicate the engine is from a 1965, for a 1200 CC, 40 HP engine.  The sequence number isn't given in my book, however, so I can't tell you when in the year it was produced.

I'm really out of my element here, as I've never worked on VW's - perhaps there is someone else on this service that can tell you more.

Dick