What canon references? I can't think of any, but I could have missed them, I suppose.
I dug up the Marches references... the "was" stats are from Supplement 3.
Shionthy (2306 Spinward Marches), was X000742-8; now C000742-8. The X interdiction was for navigation reasons, but since miners are known to be present searching for antimatter over such a long period of time, the starport was raised to C. Shionthy also had a very specific stellar change (per Marc, 9/2009).
Corfu (2602 Spinward Marches), was X895674-8, now C895674-8. Quarantined after 1065 (approximately 40 years before 1105?) due to a virulent epidemic. The X interdiction is medical, so starport raised to C. This was interesting, as Marc wanted Second Survey to be 1065, so our T5SS 1065 Marches needed a pre-quarantine starport. Marc elected to make it "C" (9/2009).
Zephyr (3138 Spinward Marches), was X89556A-3, now C89556A-5. World was founded as a food provider for Trin [GT inference], warranted improving the starport to C to provide for trade (per Marc, 9/2009). This one is interesting as GT:BtC has removed the interdiction while the Imperium negotiates with the rebels. Personally, I'd say this was already in the works but delayed by the 5FW, OR it's a post-5FW Norris change.
Victoria (1817 Spinward Marches), was X697770-4, now D6D7772-2. There are mentions that permits are available to give access to Victoria, but not the moon, and apparently someone had contacted Marc in the past about changing the TL because of the lack of metal. Marc's view was that given the existence of permits, and the paranoia of the Scouts and Navy about the system, that there had to be a location for a starport, and he opted for D rather than E (per Marc, 9/2009).
Zykoca (3004 Spinward Marches), was X994542-6, now D994542-6. GT:BtC says the starport was attacked in 1097, so it was given a starport (per Marc, 9/2009).
Lewis (3107 Spinward Marches), was X427402-D, now D427402-7. Decided to define Lewis based on the pre-Tukera closing stats outside of the estates, for Second Survey's 1065 (per Marc, 9/2009).
I could not find notes on Penkwhar or Zykoca in my quick search. Note that the Spinward Marches Droyne worlds are put into this category (non-X starports red-zoned/Forbidden) by the T5SS, but they were C starports in Supplement 3 (CT).