The 7270 could use service at this point. LED backlight would be a downgrade to me, and if the original light-pipe were altered or deleted a serious downgrade as it can never be replaced. The faceplate (glass) is NLA as original look so if it has a fairly new (but not the newest) faceplate all of the lettering on it should be gold with the lights off, with the light on all of the control lettering and the McIntosh lettering should light up green. If that is so it is good. As soon as I see LED conversions on vintage McIntosh I need to look inside the unit to see what was altered to make this work, and what else was altered. Hopefully it's just filled with LED replacement bulbs, no other changes.
On the C28, there is a fairly time-consuming service necessary to correct grounding noise in the crimped ground/shiield shielded cable. Again the orginal look faceplate is NLA, so if it has a great original or Mc replacement where as mentioned above all lettering is gold with lights off, and all lettering other than the PANLOC lettering lights up green you are in good shape. If the PANLOC lettering does not line up properly with the panloc buttons then it is aftermarket, if the lettering around the controls is not gold then it's new McIntosh garbage. "recap" is such an ambiguous term that is used by flippers and anyone trying to make a quick buck, that I give it no value at all and it means I need to look inside to ensure it hasn't been altered / hacked.
I'd like to believe that a C28 in perfect condition is worth $1,500+ (because mine would be gone!) but realistically I'd say that without the ground repair, in good condition with a cabinet it probably isn't worth more than maybe $1,100-$1,200.