Is there a screw missing from the right dropout?

No, only the cover is missing. The hole is only needed for Stromer with the older TMM sensors P178 and the newer model P211 (Gen. 2). The sensor plate is mounted there with 3 screws in the dropout. The latest sensor, the P218, only has 2 screws for mounting. The superfluous hole in the dropout is covered with a rubber cap.
> Sensor types: See under TMM-SENSOR - 'Sensor types'
> Menu structure OMNI: See OMNI / Display V1, V1.1 - 'Omni flow chart'