Numbers on the drop out or bottom bracket will tell the year. There will be two sets of 5 digit numbers, one will start out with A, C, or P and the other just 5 numbers. The ending number of the 5 digit strings will usually match, and give you the year. The non-prefixed 5 digit number string is the catalog number. Catalog numbers end with the model year. I've found this to be correct for all '80 to later '80's Huffy bikes. For instance, I have a 1980 and 1982 Pro 2 in yellow/blue. The '80 numbers are C81150 and 23820. The model number is 23820. My '82 has A80672 and 23722. Again, 23722 is the model number in the catalog. Continuing, my My black/yellow '82 ST Racing has C80112 and 83862, red/black '83 Pro 2 has C80833 and X3723, a BMX 38 frame I have has C80711 and 20381. My '84 Pro Lightning has C80764 and 33944. Making sense???