Advice on Old mill retrofit? + tool type

I'm pretty sure they are rotary encoders. There are no scales to be found around the rails or saddle.
There is a small unit on the back of the motor, labeled ERO 115 200, when googling it, it comes up with Heidenhein encoders from other bridgeports.
Worryingly most of the posts are people seeking documentation or replacements

Do you think Hardinge would be willing to sell you some of the documents you need if you asked them? I just got mine for a Maho retrofit from DMG Mori, though it cost an arm and a leg. Wouldn't hurt to make an inquiry probably.