I wouldn't say the chances of them finding out after the fact is almost zero. It's a known fact they perform random checks on applications to catch fraud and I wouldn't be surprised if they run another cursory check after oath to flag any criminals.
Many petty offense may not enter FBI records. I personally believe such a chance is very small. But
if one hide it, one will not have a peace of mind, He is always worry he will be caught one day.
Life will be like that of a fugitive.
I am not sure if the OP is innocent and is just wrongly acused. I can not
imagine anyone after all these naturalization process plus previous green
card process still intentionally make such an offense in such a critical period
between the intervew and oath. Anyone at this point should fully realize
consequences of such deeds. It is not like some offense for which offender
do not even know it is illegal to do such as one can be arrested for gambling
becaus ehe does not know playing a poker game for money is iigeal in his state.
Neither is it like the other kind of offense like reckless speeding when one is not aware
he is driving that fast. But theft is different. We all know theft is a crime and it is morally
wrong from ancient times in all cultures.
Sometimes we better be careful when shopping. Always check twice when checking out.
You don't want this to happen. You have 30 items in yoru shopping cart and paid for 29 items
but forgot one. Then you push your shopping out out of the supermarket and that
one unpaid item alert the store.