Power cords for vintage gear

Have some old Mcintosh MC 60s with real old power cords. A couple of people who should know tell me as long as they're in reasonably good shape not to worry. Should I worry?
A lot of classic gear is more valuable when left intact, in spite of best effort of owners modifications are often frowned upon.

That being said, if you want to upgrade the stock cord a good quality modern version will sound as good and possibly better and probably safer too.
I am assuming it is a captured cord. If the cord is supple and in good shape leave it alone in order to maintain it's originality. The next owner can decide if they want to 'modernize' the amp and put in a removable IEC type cord or even just replace the original with the same but new.
Sonics and resale aside, a 60 year old power cord can present safety issues. Worth at least a professional appraisal for safety.
As usual, Albert is correct though i might add plugging into a surge protector so any shorts are a hit taken by the strip, not your vintage equipment!