Technical Engine rebuild question

[124spiderman]

Hi.
I have stripped down my 650 engine and noticed that the rear main has an "o" ring between the block and bearing carrier. It is not in my newly purchased gasket set. Only the centrifugal oil filter one.
The part people I purchased gasket set from say there isn't one.

Should there be an O ring here as its also not showing in my Haynes manual?


Thanks

 

[the hobbler]

Morning Spiderman;
According to my Fiat 500 parts manual (original Fiat publication) there is only a gasket between the crank-case and the bearing carrier---part number 986964. I can't see that the 126 engine would be any different.