1897 Queen Victoria One Penny Coin ( P Or D Inside The O For One) Please Help Why This Is

I wonder if it's a rub-down Letraset 'p' or 'd' that has got detached from its backing and landed on the penny. You can get them in very small fonts - I've seen railway modellers use them to put names and numbers on locomotives and railroad cars. it can't have been there long, otherwise it would have worn off while the coin was in circulation. If I'm right, it should come off if you dab a cotton bud in acetone and gently rub it across the 'O' of 'One'.

thank you coinfrog and thats interesting NumisRob
would a vinegar solution or nail varnish remover do for this job?
i could all ways take a video whilst doing it and then you can see if that is what you say it could be.
thanks

Or a lower case d?
Wouldn't have been done at the mint. This is likely someone messing about with letter punches so although odd looking and unusual the penny would be considered to be exhibiting PMD (post mint damage).
Not to worry, as with your 1919H penny the coin is so worn anyway it wouldn't have been worth anything without the damage.