For the time being, yes. The limits are based on the AIA size as it is sent to the buildserver. We have more flexibility on code.appinventor.mit.edu because we control the tech stack versus ai2.appinventor.mit.edu.
If you have access to a Mac, you can do this. Like an APK, an IPA is a zip file. Once you've added the new assets you would need the codesign utility, which is part of Xcode, to update the signature before loading it on your iOS device or submitting it to Apple.