Very nice example and unusual to find it with the level and pressure gauges. So far I have only seen this configuration used on a 1381.
@Nils Stephenson Must say that I didn't know there was such option like fuel gauge even available for Primus 991... until I saw this lamp.
The first time I have seen the level gauge mentioned as an option is in a catalogue from 1945, but it was obviously an option before that. Otherwise they only mention the pressure gauge in the earlier catalogues.