Telefunken have changed the values of some components in the ELA M251e (C12 also), for these you can not use the schematics of the old M251e from the sixties. The two components on the left and the right side of the ROHM capacitor are 100% resistors. About the codes I`d already wondered years ago and I still don`t have an explanation. But what I know: The resistor on the right side of the 10nf (10000pf) styroflex should have 10M (can you measure it?). The one on the left, I`m 99% sure, 50M. This resistor is there to keep the voltage on this place at 0V!! To measure the 50M with your multimeter you take a resistor with a value you can measure with your multimeter and then measure it parallel with the 50M (or whatever it is, you will find out). Then you can calculate the value of the unknown resistor. There is a lot of information in the web how to calculate resistors in parallel.
If the sound of your mic is "smaller" as in other microphones of the same serie then these resistors are not the cause for it. Same I´ve seen in several M251e. Maybe your mic get`s to low voltage, did you measure the outputs of your powersupply?? Should be around 110VDC and 6,3VDC for the heater (measured with load!!). You can do this in the microphone or/and the powersupply. Be very careful, there`s high voltage in the psu that could kill you!!
The components in the mic are much stronger as needed, I can`t believe that there`s a damage.
One question: the 10nf capacitor (ROHM) seems not to be the original by telefunken. The red ring on one side means 160V (not means +!!), that`s still ok, but usualy 400V (or higher) are Telefunken standart. The red ring also shows the side with the outer foil and should be connected to ground. In your mic it`s connected to +. Did you do this? If you or a friend did it: have you tested the capacitor for ESR, Vlost etc. before using it? Maybe this capacitor has a leakage (if not the original by Telefunken, as it seems). To measure this capacitor you must desolder it on one side. Cheap LCR-meters often can`t measure capacitors under 100 or 200nf. So don`t wonder if your inductance meter doesn`t show a result.
At last: do you use the original JAN GE 6072a or is there another tube inside the mic? There are only very few tubes that can be used in the M251e to get a good quality of sound. EH-tubes etc. will not bring the sound you expect from this mic and shouldn`t be used in such a high end microphone.