5 lire 1870 papal states, silver, Pius IX [gelöst]

I have this coin with a strange ALP engraved next to the R, under the date. Does anyone have an idea what that is and where it comes from?

Thanks

It seems handwritten, it is the year of the capture of Porta Pia.

Yes, it's the last year of the Papal States, but how does that explane this inscription?

I think I have the answer. ALP stands for alpaca which is one of the names for maillechort which is a type of zinc. So that would mean my coin is false and not made of silver…