Actually, the lion stamp is from the proof house. I don't know the name or city of the proof house, but most European arms makers employ a third party to inspect and test their firearms before sale. (For trivia buffs, the lion is symbolic of the white lion of Bohemia.) This flare gun may not have been used by the Czech army, but if it was accepted by them it will have a little Roman sword stamp. They used that sword symbol on their uniform buttons before and after German occupation, even under communism. If it was accepted by the German army, it will have the eagle, wreath, and swastika stamp.
Keep in mind that there are civilian uses for flare guns, such as signaling from boats. Also, flare guns were exported widely.
Scott