To augment the comments already made, some barrel lenses can be adapted to modern, or no-so-modern leaf shutters and used in the conventional manner on LF cameras. S.K. Grimes offers such adaptations, for example, but it's not an inexpensive process as considerable machine work is often required. As such, the attraction of the originally inexpensive lens is often offset by the additional cost.
For many LF applications, where exposure times are long (several seconds or longer), "lens-cap" or "hat" shutters are used, as in times of yore. (pull the dark slide, remove the lens cap, count the seconds, replace the lens cap)
Just be cautious of lenses from the bottom of the barrel.
