but that is 4 years later than the xerox optical mouse tech report, and from a different company which copied their default mouse pointer style from xerox. it doesn't bear on the question of whether xerox was implementing cursors without hotspot coordinates at the time that they adopted the left-leaning shape

(i suspect xerox mouse cursors always had variable hotspot coordinates because it's, what, six microseconds extra in the screen update to subtract them? and i think smalltalk-76 mouse cursors have hotspots. but 01988 or even 01985 is way too late)