One thing is for sure, you cannot use flat top in the new battery carrier. There will be plastic insulators on the anode (+) ends to prevent loading batteries in reserved direction. I suspect you can remove them but you will risk damaging the batteries or even light if you make a mistake for the polarity.
The cells are paralleled at the battery carrier. Put one in backwards and two cells will be shorting each other out before you can install the carrier in the light.
It’s an important safety feature and should be there.
If someone (you, your wife or your kid) puts a cell in the carrier backwards, two cells short with a strong possibility of venting or bursting into flames right in front of their face. Drop the thing in the wrong place and your house catches on fire.
It’s much better to use the correct batteries or add solder tabs.