Without shimming, it will be a gamble. Very difficult to get the voice coil centered in the gap that way, and high risk of rub; it may not be noticeable until high Xmax. Not saying it is impossible, but high probability it will not be centered.
Not sure what style dust cap that has, but if it is factory, it is likely a rubbery adhesive holding it on, heating the glue joints of the cap (high heat setting on a hair dryer for a while) and slipping the end of an old credit card under it may get it off without cutting. Also may help to sand the edge of the card so it is sharper. I’ve almost always been able to remove factory caps without cutting it / damage. I would personally try that first to see if it starts to work, as shimming the coil would be best.
But if you feel like it will be damaged, could go for it without shims.