Yes, that's working
All Info about this new feature:
Anti-censorship team meeting notes, 2023-06-29
https://lists.torproject.org/pipermail/tor-project/2023-June/003642.html
== Announcements ==
rdsys is ignoring the running flag now 
* To hide your bridge's ORPort:
ORPort 127.0.0.1:auto
AssumeReachable 1
The previously mentioned logs and the Tor metrics showing the bridge as offline can be ignored.
https://metrics.torproject.org/rs.html#details/E6709F6130C61638400F27FAC6358E3412790F72
···
On Montag, 31. Juli 2023 23:06:54 CEST Gary C. New via tor-relays wrote:
Please let me know, if you are able to get the OBFS4
bridge working without exposing the ORPort. Respectfully,
--
╰_╯ Ciao Marco!
Debian GNU/Linux
It's free software and it gives you freedom!