@wetterdew No idea without a photo; however, wing buds are present in several of the later molts clearly, they just get bigger with each molt. A quote from Peter's general mantid caresheet...
wing "buds" (these get larger with every molt, eventually becoming full wings for most species in the pet hobby)
Yep the wing buds become more noticeable the larger the mantis gets. The wingbuds are very pronounced in the last couple if instars for Carolina mantises so simply seeing them does not mean the mantis is a sub adult. If you aren't familiar with the species the only way you can use the wing buds to judge if the mantis is a sub adult is by the fact the wing buds will get very plump as sub adult mantises get closer to their molt.
You guys were right! One of my mantises molted and she still only has wingbuds! Also I'm pretty sure they are actually Chinese mantises instead of Carolinas, because they're getting way bigger than 4.5 centimeters.