Need block casting ID help

from what i gather the D and N stand for day and night (as in the shift the factory was on at the time of casting) however I didnt notice which letter the pointer was aimed at (ill look some other time) also,there is a casting of a clock and its aimed at the first dot after 12 o clock so I am thinking it means 1 or 2 oclock when it was molded.

as for the 7 dot 27 dot 66....I assume it is the date 7-27-66 which since it is past the half way mark of the year (6 months) it would have most likely been in a late 66/ early 67 model vehicle.

also from what I gather the 2536030 318 stands for 318 1967-1975 LA ......but from what I gather LA blocks did not start until 67 and if this blocks date was casted as a 66 does that mean it is a 318A block? or since it was after half way through the year by the time it was casted it was considered a 67 and considered a 318 LA block?

sorry for all the questions....kind of confused and looking for any expert advise and anyone that can give me any more info than that of what I think??? I know lol.

Thanks all