Broadsider96

I have recently started to renovate a Jap engine and looking at various web sites I cannot find one to date the engine accurately . The engine No is RC 30771 stamped on the crankcase , there is also another No which is difficult to see but is either WS 8623 or WS8528 The barrel has the No H 11238 The flywheels do have the No 1950 on them but unsure if this is a year No . Any help in this regard would be appreciated .