I have managed to find a number on the key tumbler. There is a 5 and another mark. Being a Canadian car, would there be a difference in the way they were marked. If a photo is required I will post one as well. I have just had new prescription glasses made so I don't think it is my bad eye sight.
Keys and tumblers are numbered from 51 to 72. If your 5 is in the tens column, your number is somewhere in 51-59. If it's in the ones column, your number is 55 or 65. The tumbler numbers are often hard or impossible to read because of corrosion, wear, damage, being poorly stamped, or being filled with paint. Sometimes adjusting the angle of lighting makes the number readable.
Of course if you have an early Clum tumbler, their numbers are different.
Do you have a photo of a different # than 51-72 for Model T key?
Here are early '19-20 switches, the ones with the heavy cast lever in plate. The shiny painted is marked 'Clum' on the pin-back style terminal disc. This one is the 4-rivet face switch.
The other in rust is similar with pin-back style disc, but has the 2-rivet later looking face switch. But both have cylinders marked with normal 51-72 series numbers for the key.
4-rivet, the Bat and Mag stamped on the black plate (small, hard to see)
2-rivet, the Bat and Mag stamped on the cylinder face.
Try taking a real closeup picture of the number with lighting from the side to create a shadow effect.
I did this and was able to decipher the number.
I don't have a picture of it, but I do have a very early 1919 switch with a #16 key and tumbler.
The switch is round, with the Ford script, and is nickel plated. This was to be used on the very first fabric covered wooden dash boards, before they came out with the common retangular switch. For years, I've seen a guy at Hershey with a Clum keyboard. It looks similar to the Ford keyboard, but says Clum at the top, and has about the same number of keys on it.
I think that this thread may have the switch you mention .
Yup, that's it. I've got two of those amp gauges also, but the bezel is not nickel. Does anyone know who owns the car pictured? It would be interesting to know what the number is on the key.