In most examples, the filler will be the standard aluminum speedline filler used on the Vacumatic line of the time, although not all "first year" examples have the speedline aluminum filler. The Extra Fine point is remarkably smooth. Nicely frosted cap with one obvious rub of the frost where the clip moved against cap can see in pic. It is at this point all silver. GF "Converting Lines" Cap.
Fine Point for the pen.
Dating An English Parker 51
I've forgotten my password. Parker Esprit. Lustraloy Cap with Gold-Filled Clip. I wish there was more info on English P51s as well. Cap has early style long clip and filling unit is early style "press six times" chrome finish with couple flakes common to the chrome on that hidden filler. What passes for my experience suggests the prevalence of Midnight Blue is more on the order of Forest Green than of the more common colors to follow.