Hello Patrick. Interesting you should raise this question now. There is a pair of these on the front panel of the 52-Set Supply Unit I am keeping an eye on now. My two still have very supple, flexible sleeves but the state of the actual grommet ring surrounding the panel is still unknown. I am hoping they will still be soft enough to remove and reinstall safely.
Sleeves grommets were extremely common fittings years ago and the numbering system for them leads me to believe there was a standard form of sizing system for them which could make finding new ones today much easier than it might otherwise be.
Having seen the photo of the one you posted, it looks like different suppliers may have met the ‘No. 2 Standard’ with subtle variations in design. Yours has equal sized rings for either side of the panel at the grommet end. The ones used on the 52-Set have an inner ring with a smaller outside diameter, which would make installing and removing them a lot easier if they are getting old.
A good starting place for new replacements would be the following company down in Westchester, Illinois, though their Corporate HO is in the UK somewhere I believe.
www.essentracomponents.com
If you can, send them the actual specifications from one of the wireless parts manuals as a reference guide for them to work with.
With regards to reconditioning old, hard rubber, there are a number of products out there that work to a point, but I would suggest you stay away from anything automotive. The tyre ones are far too aggressive on the rubber for thin items and the rest tend to be of a wax and polish kind of thing that coat the rubber to make it look new but just add more layers of crud to the rubber in the long run.
What you want to find is a rubber rejuvenator used for rubber patens or rollers as in old typewriters, or newer printers and photocopiers. These will soften a thin depth of the rubber, which might be all you need for a thin sleeve. There are also some rejuvenators out there for treadmills, but I would stay away from them as well as they have a significant lubricant element to them.
Hope this helps, Patrick, and I like the way your turret is going.
David