Hope this will help some of you who want to know what those little indentations and stamp marks are on your precious metal Parker pens. I had customers back in the 80's who thought that these were defects or dents in pens such as the '75' and the Premier. A 10X to 22X loupe should do the trick in ascertaining what the symbol is, then compare it to the list...
Hallmark List from the mid-1980's...

ENJOY!
Docnib
PS--I had a Pelikan nib the other day with 2nd symbol under 18CT Gold (French Assay Office)...curious!