Hello @ all,
i have made a small compilation about NARVA mercury-vapour lamps designation.

Source: NARVA information for the practician, high-pressure mecury-vapour lamps NAVIFLUX, 1979
The composition of coding is explained in fig.4

Source: NARVA information for the practician, high-pressure mecury-vapour lamps NAVIFLUX, 1979
Table 1 explains the assignment of figures for bulb-shape and design version.

Source: NARVA information for the practician, high-pressure mecury-vapour lamps NAVIFLUX, 1979
Table 2 shows the delivery programme of NARVA mercury-vapour lamps in 1979

Source: NARVA information for the practician, high-pressure mecury-vapour lamps NAVIFLUX, 1979
Table 3 shows the dimensions of NARVA mercury-vapour lamps, table 4 shows the electrical data.

Source: NARVA information for the practician, high-pressure mecury-vapour lamps NAVIFLUX, 1979
Table 5 shows the lighting data of NARVA mercury-vapour lamps.
Hopefully this is a little help and answers some questions about the coding and the technical data of the NARVA lamps.
Greetings from Hamburg
Olav