This is an interesting prototype in that it has the same material as found in prototype 22. The difference is obviously that this is smooth, completely devoid of any pattern. While I am uncertain about the material used, I can say it is lightweight. My guess is that it is made of stainless steel or aluminum.
A close-up of the cap band area shows that there are no inscription on this FP, confirming its status as a prototype.
Also notice that this FP uses flat tassies just like prototype 22, indicating that it is a rather early prototype prior to 1970.
