Victoria 1839 Single stop after DEF.
First A of GRATIA unbarred with the impression of a single stop but the top colon has faded away after DEF.
There were more coining machines minting Victorian farthings than you can shake a stick at and to list every die and name it by number or letter would take all your life and you would still miss some. For a farthing runs of millions any missing numbers or letters would dealt with right away or at least when they were spotted, but stops or colons probably wouldn’t have been as important. As for missing colons they only seem to have been a problem in the early years except 1853 which was a massive mintage regardless of what coin catalogs say and fading colons could be expected for that year.
Take the 1717 & 1718 halfpennies which had a large mintage all have a strong reverse stop ( except the 1723 which most collectors have never seen ) and reliably two weak obverse stops. Most dealers have reliably got either year for sale with both obverse stops missing listed as extremely rare, but a lot of internet sellers are the winners of taking advantage of production flaws and quoting some out of context reference from a well know book insisting its extremely rare.
Do not read to much into missing stops or colons as there’s always a sensible answer. Its rare for more than one set of colons to be defective or missing, so if a defective colon punched was used then surely all the colons would be defective on that farthing and given the amount minted its nor surprising they faded away along with shamrock stems, helmet plumes, trident staffs the list is endless, ! ok at least very long. Another thought to take into consideration is this die was used for George IV and William IV and was already eleven years old. Sensibility and logic always prevails as the evidence is nearly always there.