Propeller Changes

Blade Number

With the exception of a single prototype unit (an XA-26D), all of the Invaders that entered service were equipped with 3-blade propellers. The XA-26D Prototype had four blades.
Typical 3-blade configuration.
The single 4-blade prototype.

Prop Spinners

None of the Production Invaders were equipped with a prop spinner. The only models that featured prop spinners were the prototype models and civilian versions.

Blade Shape

The B-26K CounterInvader models all had square tipped blades. The vast majority of the rest of the invaders had round tip blades. The single exception that I have found for this is one plane in the 8th Bombardment Squadron, 3rd Bombardment Wing named "Toc San". It's flown by Lt. Larry Bray during the Korean War and, at one point, it does have square-tipped propellers. It is not clear if this was a battle-field replacement for a damaged blade, or an experiment, or something else. But none of the other planes in that unit have square blades.