Oops, Paul is right here - I asked bug-coreutils@gnu.org, and Paul
responds:
<quote>
Re: bug#8578: 8.12 and 8.10 'ls -dl' appends ' ' (0x20: space) to file  output lines
From:  Paul Eggert <eggert@cs.ucla.edu>  (UCLA Computer Science Department)
  To: jason.vas.dias@gmail.com
  CC: 8578@debbugs.gnu.org
Date: 2011-04-28 20:34
   
On 04/28/11 11:34, Jason Vas Dias wrote:

> $ ls -dl /. | od -cx
> ...
> 0000040   r       2   0       1   5   :   2   8       /   .  \n
>            2072    3032    3120    3a35    3832    2f20    0a2e
> 0000056
> 
> Please could the ls developer let me know if it 100% POSIXLY correct
> that ls appends 0x20 to the filename '/.'  here ?

I don't see any space appended there.  The last four bytes of
output are 0x20, 0x2f, 0x2e, 0x0a (space, /, ., newline).
Perhaps you're misunderstanding the little-endian nature of
od -x output?
</quote>

Yes, of course, when 'od' says ' 2f20    0a2e' it means it received:
  0x20 0x2f 0x2e 0x0a
sorry - I'm just trying to understand why your original RE fails -
it isn't because of the spaces !