Frp inlet question

[Northeastpuma]

Just enquiring, does anyone know if there are any un numbered inlets ever made. If so are they rare

 

[Flying Scotsman]

There are two 'blanks' (without numbers machined into them) in circulation, so yes thats pretty rare.
There are also one confirmed, 3 suspected 'casted' (nothing at all machined into them).

 

[Northeastpuma]

Nice one cheers