If you mean a choke bored barrel, it designates the amount of constriction a shotgun barrel has.
Improved cylinder
# They relate to choke type, i.e., full, modified....
4 notches = cylinder choke (open), and one notch = full choke (tight)
It stands for Modified choke.
They probably denote what choke the barrel has.
Degree of choke
Go here for a good explanation - http://hunting.about.com/od/shotgun/l/aastshotgunfaqa.htm
yes it is a choke marking. What you list doesn't follow the normal convention.
it is part of the choke codes. '*' designates full choke (F). '*-' designates improved modified choke (IM). '**' designates modified choke (M). '**-' designates improved cylinder choke (IC). '**$' designates skeet (SK). '***' designates cylinder bore (CYL).
Best guess: You have a shotgun manufactured in Croatia. "Pun" means "Full" in Croatian. "Pola" means "Half". You would have something like 70% constriction in the Pun barrel and 55 to 60% constriction in the Pola barrel.
Browning Choke Markings "* " = full "*- " = improved modified "** " = modified "**-" = improved cylinder "**$" = skeet "***" = cylinder