I believe it only matters if you have a 100 point bike in a bike show, where the judges might mark down points for having the wrong banjo fitting in the machine.
The earliest of the BSA machines relied on an oil mist to lube the rocker systems, they did not have an oil banjo fitting to feed actual oil to the rockers.
When I first got my machine ( 43 years ago) the P.O. had cut the banjo tube off so short you could not get a clamp on to seal hose properly. Could not find a replacement banjo fitting at the time so had to drill out the 1/8th copper tube from inside the banjo and silver solder a new 1/8th , exterior measure copper pipe in it, with an internal diameter of 3/16 th's, and then run new rubber feed hose up to the Webco rocker feed at the top of the valve train.
PS: When first starting your machine, while looking into the oil tank for sump oil return oil, hold your finger over the return hole to tank and force some oil up to rockers, then you are good to go for max lubrication to the rocker arm assemblies. Remember BSA relied only on oil misting for years. You do not want to hold your finger there too long, you could foul a plug eventually, you can hear from the valve clatter when it is enough oil up there, it quiets down some.
