What you have are two screws, 42067-S and 42127-S, with identical threads, 10-12, the same length, 1/2 inch, and different heads.
42067-S2 is only called out (for 67,68) as being used at the heater to clamp the control cables. No other finishes were specified. I would assume that the clamps and screws were pre-assembled before installation.
42127-S2, -S36 and -S8 are called out several times for use in and around the heater and air conditioner units. That would make it a good replacement for 42067-S2 if necessary.
It would be an "oddity", not a standard.
Jim