I'm finally pulling apart my 67 for total restoration. It is a fairly original car but very deteriorated. The booster, which looks like it has never previously been off the car, is confusing with regard to the numbers on the tabs. The 10 o'clock tab has the number 309 and the 4 o'clock tab doesn't appear to have a number. All the visual characteristics of the booster look correct and the master cylinder is original to the car. Anyone have any thoughts or experience with this booster? Thanks