Dunlavy sc-iii rubber surround separated from cone

Hi all,

I recently purchased a pair of dunlavy sc-iii's from here on Audiogon and whether it was an existent condition or my fault, I now notice that the rubber surrounds on two of the mids have separated. One of the mids has about half the rubber separated while the other is just a tiny area. Is this a serious issue or can it be fixed with glue? If this is fixable, can someone recommend a proper glue and how should I go about fixing?

Also, is this issue expected due to the age of these speakers? I'm thoroughly freaking out because of the effort put forth in acquiring these speakers after much research and reading up on the comments posted on here. It could also have been my fault -> I was switching sources from phono to CD and didn't check the volume, which was set up high on phono. Can someone please calm my nerves?

Thanks for any help upfront.