I'm not sure how to accomplish this, but I might have an idea of what needs to be done.
data_0.rpf\data\itemdatabase\catalog_sp.rpf\0xCF8DA776.ymt
this is the item database file that appears to be referenced by catalog_sp.ymt, and I think it just needs to be modified to match the added texts in catalog_sp.ymt
The hashes should be able to be relatively easily decoded using <tags> under the item keys in catalog_sp.ymt and by comparing the tags of an nonsell-able item (cigarettes, etc.) with those of an sell-able item (pineapple, etc.). There are 10 consistent key omissions under tags with type 0xC76BC07D that happen to be common for these unsellable items.
Some items have many different item variations, these are examples of some that should be the right ones:
<item key="CONSUMABLE_CIGARETTE_BOX_CHEAP">,
<item key="CONSUMABLE_CIGARETTE_BOX">,
<item key="CONSUMABLE_COCAINE_CHEWING_GUM">
which should include some changes like the following:
I hope my work will be able to help some more experienced modder figure out how to accomplish this, even if it's not entirely accurate.