I am in the process of restoring my 1969 RS/SS 350 Convert, and am currently doing the front sub frame and rear axle asm. My front springs still had the original tags on them but they was covered completely with dirt and undercoating. I was able to carefully remove one and gently clean it so I could read the numbers and letters. It reads EM 3955712. Which is correct according to the spring chart for the options I have. The rear spring tags are missing. The rear end is original to the car (12 bolt 3.07 Posi code BR) and has 5 leafs. According to the spring chart, should the rears be BF or BN tags? The option weight is over the 16 lbs listed in the chart. Also, I cannot find any vendors who list these tags neither front nor rear. In another post, someone mentioned ECS, do they make tags not listed on their site? Any help would be appreciated.