Glad to see a plate up close.
My contract number is S7218 - 37

email (option): ccandgc@yahoo.com

S7218 probably had the later type of steel contract plate - this is from Norton contract S5161.

I don't know if yours will be the same font ,it was a lucky find coming up with the identical contract as mine , I think I've found the stamps with the correct font .

email (option): davemb42@yahoo.com