I have a surplus SEIKO #0 shutter available. Timing and speeds are good down to a full second. It’s pictured without the retaining ring on the back but it IS included.
The LS44 aperture scale is for the 125mm f/5.6 Fujinon-W (the original single-coated version with the lettering on the trim ring and visible from the front, not around the outside of the barrel). It starts at f/5.6, but the position of f/5.6 is specific for this 125mm lens. It will be incorrect if you install cells with a different focal length, and the amount of error will depend on both lens design and focal length.