Jase. Early tanks have no rubber mountings and the same basic pressings could be found throughout the BSA range, adapted and modified to suit specific model trims as noted previously. Tank bottoms also vary, depending on the tank capacity offered and the differing height between A7 and A10 Motors. A large capacity tank will always fit an A7, not always the other way round.
Front brake types can be mixed and matched along with their corresponding fork legs, as the fork bushes and stanchion diameter remained the same throughout production. The brake anchor type, peg, slot or torque arm is the decider along with the yoke width which limits the choice on very early models. Frame head bearings are the same, so later fork assemblies fit early frames.
Swarfy.