The interior color for your 1999 Sahara is called "Camel", it was available on all TJ's from 1997-2002. Whether or not an aftermarket part called spice or tan will be closer to factory Camel is going to vary slightly from part to part, supplier to supplier but both are very close in most cases that I have seen.
Remember that Camel interiors got factory tan carpets and factory tan soft tops. The factory "tan" is much darker than the factory Camel and is actually closer to a light brown.
2002 Wrangler Sahara, all stock, 5-speed, Dana 44, duel tan tops, 2nd owner.
2008 Hemi Grand Cherokee Limited 4X4, Quadradrive II, original owner, 22,000 miles.