There might be pumpkin ball slugs available somewhere in the world, but, I've never seen them. The Foster type slug has been in use for a very long time, here in the states, and in Europe.
Even if a gun with a Raye barrel didn't have the "Non Pour La Balle" marking, I'd be very hesitant to try it.
The last time I was in St. Etienne, a two man shop, using an ancient American Cincinati lathe, was the only place left cutting Raye barrels for the trade. The operator suggested to me that there were better options for using slugs than a Raye barrel.
I just put a photo of a nice, fat, European woodcock up in the hunting pictures thread.
It was taken in Sweden. I don't doubt they are rare, today.

Best,
Ted