Hi Peter
Well, what I have tried to proof in my article, is that the Fiat Dino`s are produced increasing order by the Ricambio No., and
NOT by the chassis No.
So if you open the list sorted by Ricambi No., you can see that your car with Ricambi No.
5043 must have been produced very close up to May 1971.
You can see that Modifica
4258 was implemented on Ricambi No.
5058 from 01.05.1971, so 15 vehicles after your car was produced.
So for me there is no doubt regarding the manual, I-1971 should be the right one.
The engine No. is very easy to get, just slide your mobile phone down along the engine oilfilter, with the camera facing the cylinder block. Then you can take a picture of the front of the cylinder block, just under the cylinder head gasket, there it is. This will help me place your car even closer, because of Modifica
4245. The engine number of your car will define if it is produced before or after Modifica 4258, which was Implemented in the production 01.05.1971.
Here is a picture of the engine number of my car, and you can see a little of the orange/ red Baldwin engine oilfilter down in the right side of the picture. (
if you click on the picture & open it).
BR
Erik