Being different from the standard army boots is still a long way from being rikusentai/NLF boots. Is there anything stamped on the soles of your boots? We can conclude they're certainly not NLF, but maybe they are at least some kind of army variation. However the lack of eyelets for the laces is very odd.
To set some things straight, there is no such thing as "NLF officer boots". The official rikusentai uniform regulations only listed boots for petty officers and enlisted men, which were described as BLACK leather lace-up boots, so that rules out any brown or other colored boots from being NLF. As for officers, boots were on their own dime, they could wear the standard officer pattern low boots or riding boots (which weren't solely for NLF), or buy/borrow a pair of enlisted NLF boots if they wished.
As for the above two photos, the first is undated but came from a vet who was in Shanghai around 35-37, the second was taken in summer 1933. The first photo immediately below is 1944 in case two clear examples weren't good enough. Note the eyelets and pull tab which are absent from your pair (not to mention the color difference). I've also included some footwear for officers vs their enlisted counterparts.