R.C. Allen Calculator, Adding Machine and Cash Register Years of Manufacture by Serial Number! R. C. Allen Adding Machines Manufacture Dates by January 1 Serial Number: Serial # Year Remarks Ref. 825000 & 952000 1937 Formerly Add-Index, Series changed to R.C. Allen at Serial # 825000 1 848000 & 962000 1938 1 856000 & […]