Quick question about measuring can cap values in circuit

[vortex]

I am making a layout and schematic for a small custom amp i picked up and wondering if I am measuring the specs on the can cap correctly.

The can cap itself has the 4 capacitior values written on the side with the marking symbols (square, circle etc.) but the symbols do not appear on the top of the cap where the connections are made.

I measured capacitance value from the connections on the cap to chassis ground relative to where they are connected to the rest of the circuit. (I know that the in circuit reading will be off somewhat )

Am I going about this right?

[Enzo]

Where the terminals poke though the end of the cap, are the holes the terminals poke through not shaped differently?