Oars aint ors

The Oars we are supposed to use at the top ones.  They have fatter handles.  Some of the guys don't like that and prefer the ones in the bottom of the picture.

I am going to ask Croker who are the name brand oars if we can buy just a set of handles and then get the saw out and modify our oars to make them like the other set.

Update:
Had a chat to Croker and they advised that the top oar is a "Concept" oar.  The wood bit we believe goes into the shaft about 150mm.  It will be very hard to extract the wood part and even then the Croker handle assy will not fit in.   A suggestion was to sand / rasp / turn down the handles.