I'd leave it. 22" radiators came on some 440-6 cars, so you may not need any extra cooling depending on what you are going to run.
Moving the VIN to the new one would be VIN tampering & a felony.
26" radiators were available in 1972 models.
If you do decide to change it, leave your whole top support intact & just use the lower portion of the new part to avoid the numbers issue.
Changing something like that would be enough to call it a custom vs. a restoration since it would not be returned to 'as built'.