This came up last session. The list in is Magic of Habololy for WotD, and whichever weapon is listed there (without the added magic) is the one that would be used for Spiritual Weapon.
The Oldest Orc
+1 Warning Staff
Habastly
+1 Thundering Staff
Treetop
+1 Distance Short Bow
Smofarf
+1 Spell Storing Hand Axe
Lakius
+1 Shock Spear
Dedestroyt
+1 Bloodfeeding Greatsword
Tyrogatore
Admantium Stunning Surge fists (the cleric's hands become scaled)
Compture
+1 Morphing weapon (cleric chooses initial form when spell is cast)
Han~Sui
+1 Keen Katana
Everentual
+1 Dispelling Hammer
Gruweas
+1 Axiomatic Tri-Sword
Celetal
+1 Power Storing Weapon (cleric chooses weapon when cast)
Tommimao
+1 Lucky Long Sword
Tfop
+1 Paralyzing Long Sword
Falan
+1 Sacred (good cleric) OR Profane (evil clerics) Long Sword
Lavash'Ki
+1 Knockback Cutlass
Frostine
+1 Frost Spear
Sutyr
+1 Flaming Greatsword
Dresta
+1 Impaling Dagger
Arsur