The short answer is maybe.

New IR codes require new boards and equipment in both the remote or TV or at least a new firmware or flash to both devices. It is easier and cheaper for manufactures to recycle codes. This is why I can pick up a Sharp TV remote from 4 years ago and use it to power on/off the new Sharp 4K TV.

The better question to ask is if the manufactures all use the same IR protocol and within that protocol the same device number.

For the most part, they do.  At least the major brand names do.  However, there are things that are done to cut corners.  Take the Sharp LE550 series.  It does not have any known discrete power commands, but the LE650 does respond to discrete power.  Why were these choices made?  We can only speculate.

Occasionally codes are "updated."  A "video 1" input command to a receiver from 5 years ago might work on a new receiver, but instead call the "dvd" input.  New commands are added as new features and input are added.  If a have an "HDMI 4" input command for a TV that is modern, an older TV might not respond to this command.  This doesn't mean the code changed, it might mean the older device didn't know what to do with the command.  (Imagine being handed an iphone in 2003).


Circling back around, the answer is again maybe, or one can hope.  I hope this helps.