You keep calling them "bolt-ons", Cyc, but... they're not. It's just a change in the ’Mech's geometry itself. Bolt-ons are things you add, remove, or otherwise change yourself without affecting stats or hitboxes on the ’Mech, like the Hatchetman's namesake hatchet, or the sword on the Red Reaper II, or any number of the miscellaneous attachments that have been released and available to almost all chassis.
The head of the Commando IIC is not a bolt-on any more than the extra greebling found on Prime(I) OmniMechs or those giant shields found on Onyx and the aforementioned Red Reaper II, or the alternative head sculpts found on the collector's UrbanMech (reused for the Urbie IICs) and WLF-2(R), or the deaths heads on Warlord and the loyalty version of the AS7-S. All of those things are permanent features of those ’Mechs, and some of them you can even put actual bolt-ons on them!
You keep using that term. I don't think it means what you think it means. The Commando IIC is absolutely going to have different hitboxes from its IS counterpart, even if it will only meaningfully affect the head, which most people are unlikely to hit anyway. That is anything other than a bolt-on. lol
It's different enough from the regular Commando that I'd be somewhat surprised if it doesn't come with its own cockpit; that window looks nothing like the IS Commando's.