You can but it will make no difference. Will still turn same direction. The way commutator is oriented to armature and field, it will only turn say CW as viewed from the commutator. Or CCW if a gear reduction type..
You can go ahead and try it, But, be Sure to remove all wires from starter.. Remove ground from battery. Use an external battery. Simply reversing while connected can blow alternator diodes (if fuse/fusible link doesn't go) and everything electronic on car that happens to be always on, like memory to ECM and radio.
Use WD40 to free it up.
I Sympathize with an impossible to access. starter. My sister-in-laws Honda had one easy to drop out But that last bolt needed a bit of wire to get it in there. then, a turn by hand. Pull to remove wire then use socket wrench.
Electronics tech 40 years, fixed motors, generators, cage/'sickle electrical Dad was E/M in USN 20 years plus 10 years Civil service , maintaining ship electrical.