The magical custom buffer read-only

The magical custom buffer read-only

[Lennart Borgman (gmail)]

Custom mode buffers are, at least partly read-only. I want to discover 
if a custom buffer is read-only at point, but I can't. I have tested

    buffer-read-only
    (get-char-property (point) 'read-only)
    (get-text-property (point) 'read-only)

and

    (command-remapping 'self-insert (point))

I think the last one should work since in custom-mode-map there is a 
remap like this:

     (define-key map [remap self-insert-command] 'Custom-no-edit)

Is this a bug or?

Re: The magical custom buffer read-only

[martin rudalics]

>    (command-remapping 'self-insert (point))
> 
> I think the last one should work since in custom-mode-map there is a 
> remap like this:
> 
>     (define-key map [remap self-insert-command] 'Custom-no-edit)
> 
> Is this a bug or?

Does

(command-remapping 'self-insert-command (point))

work better?