HMV 4 soundbox question

[CharliePhono]

Am considering the purchase of an HMV 101 and wanted to ensure I know the difference between the pot metal and brass soundboxes: To be clear, the version upon which the mounting flange sits a bit proud of the back of the soundbox is made of pot metal, correct? Is this always the case? I understand that if the flange is flush with the back of the soundbox it is brass, yes?

I have my eye on a very nice one, but if the above info is correct, it is equipped with a pot metal soundbox, which I wish to avoid. Thank you in advance.

[epigramophone]

First Type c1925/26 all brass with writing behind the mica and flush fitting rubber bush.

Second Type c1926/28 all brass with writing on back and flush fitting rubber bush.

Third Type c1928/29 with pot metal backplate, brass bezel and projecting rubber bush.

Fourth and final Type c1929/31 all pot metal with projecting rubber bush.

The pot metal backplates can also be identified by coarser milling on the rim, but for that you also need an early soundbox for side by side comparison.

[Phono48]

Be aware, though, that the rubber bush can easily be taken out of a brass soundbox and installed in a pot metal one. As said in the above post, the only certain way of telling is to examine the milling round the edge.

[CharliePhono]

Thank you, gentlemen.