I wouldn't assume anything about these adapters. My guess is that the M5652 adapter lacks the overcurrent protection circuitry of the M4662 which makes that "universal" replacement usable across the entire 100 series, with the notable exception of the PB150 according to the linked chart.

I'm also wondering if the M4662 is safe to use with the Macintosh Portable. It's not listed as compatible, but the table is for PowerBooks, which excludes the luggable.