I have a general question regarding how Harley Davidson issued production numbers to each model or in total (first bike on the production line - to the last)? Was it by model or just 1000, 1001, 1002, etc.? I'm looking at a 1953 FL with numbers 4507. How do I verify this is accurate? I know from reading that there were 1,986 FL's and 3,351 FLF's produced in 1953.