The internals for the AH La5FN and the La7 are based upon the layout inside the La7 which was noit the same as the La5FN
Dials were actually as below.

1)Hydraulics pressure gauge
2)Flap index
3)Landing gear control lever.
4)Brake pressure guage
5)Air system pressure guage
6)electrical switches
7)Landing gear indicator
8)Clock
9)cannon air charging
10)Altimeter
11)Cannon manual/mechanical charging
12)Cockpit vent (N.O)
13)Gun sight
14)Compass
15)Course indicator (N.O)
16)CI reversing switch (N.O)
17)Amperemeter
18)Fual Guage
19)Cockpit light
20)Radio compass switch (N.O)
21)Cylinderhead temp guage
22)Frequency switch
23)Vertical speed indicator
24)Oil temp, Oil pressure & Fuel Pressure guage.
25)Turn & Bank Indicator
26)RPM
27)Boost
28)Airspeed indicator
29)Ignition/magneto switch
so your empty hole is for the magneto switch.
Where the text says (N.O) it means this was added post war (in this case by the Czech airforce) You will note that we have an additional G meter which I suppose makes some sense as we cannot feel G.............. we can see horizons however as much and as little as any VVS pilot could.