Normal DEF : for type 1 Top colon dot tilting backwards CP 1858 Aa & D's
The 'top colon dot tilting backwards' has been found only on examples of :
CP 1858 Aa (Type 1 - Large date - Date: 8 over 8) &
CP 1858 Dc (Type 1 - Date: 8 over 7), so far !
Both colon dots closer to DEF & the top colon dot also - tilts backwards:
CP 1858 F (Type 1 - Smaller numerals)
There is no trace on either of the mis-aligned examples of a weak or worn top colon dot - in the supposed correct position.