8 speed drivetrains have rear cassettes that are spaced farther apart than 10 speed cassettes, so the 8 speed has a wider chain. Thus the spacing on the front crankset is slightly different to accomodate the width of the chain. There is some leeway in mis-matching a chain & crankset. It's more crucial that the chain match the cassette.

On my rain bike, I have a Campy 10-speed drivetrain, but am using a 1985 "5 speed" crankset designed for a wider chain .... I thought it might "half-shift" and get stuck between the chainrings. No problems though, works perfectly.

PS, I'm surprised 54-42 is available on a bike now-a-days without special ordering.