B&W Matrix 3 Series 2 - To mod or not to mod?

Hi, I have a pair of very nice Matrix 3 Series 2 with one major flaw. The dustcap on one of the midrange drivers has come off and was subsequently stepped on and destroyed.

I contacted B&W and ordered a replacement along with an extra in case it happened again. The ones they sent were not the same. When I called back they said that those were the only rubber ones they had available.

I've been trying to convince myself to sell them, even though I don't want to, due to the downsizing of my living arrangements and financial issues. So, my questions are, would I be better off selling them "as is"? With the new, incorrect, larger rubber dustcaps from B&W on all four drivers? Or another option I've been thinking about which would be if I'm going to replace them with incorrect replacement parts to use a stiffer plastic piece instead of the soft rubber ones. I like the idea of adding more ridgidity to the cones with the stiffer replacements but I also feel I would question somebody elses "modification" to a nice pair of speakers.

Any thoughts or ideas would be greatly appreciated...