Yes, that's a 75R attenuator (and also has belling-lee 'TV' connectors, as well as not going down to DC for some reason)
I was thinking more like these ones: (RS-Pro are twice the price!)
https://uk.farnell.com/aim-cambridge...3db/dp/2357851
And may be able to pick up used / faulty ones, even cheaper to strip-apart.