SC 1573 restoration

[Tribune]

Got a Stromberg Carlson 1573 3-line unit that's next up for cleaning and restoration as part of my slowly developing "Black 500 look-a-like" collection.

The unit I have is the same as on Paul-F's website, except his is rigged for wall mounting.
Paul-F's SC 1573



Firstly though, how the devil do I remove the dial centre without damaging anything? It appears to be a (very yellowed) clear plastic insert within the metal finger wheel. Any way one can reverse that yellowing (Retrobright?) or source a replacement clear plastic disc?

Unlike Paul's example, mine has a little red button in the top right corner, again having suffered considerable fading. Could this be re-coloured? Dye? Maybe even a coat with a red Sharpie marker pen!?



I guess the paper(?) inserts in the selector switches that once were red with white lettering saying "HOLD" can be overhauled? Print new, pull out old and replace?



Lastly, it appears that there may have once been some kind of label or plate attached in the middle of the front of the phone. The screw holes are there and in the dirt one can just make out an oblong impression of where the label may have been. What may have this label said? Anyone have any images, or even a spare they'd like to sell!?

Currently working on a Leich 105K convertible as part of the same collection. Once that is done, I'll move on to the Stromberg Carlson. If I can find the time! And once the metal housing from my Connecticut TA-166/U comes back from the chrome shop, I'll have that to finish as well!!!