Date of manufacture & date of occupancy

Given the clear credit language, I would probably say you can't earn the credit using only the furniture purchased in 2008. If it's important to you I suppose you could try documenting it, include a narrative, and hope that it gets approved?

Depending upon the furniture and who makes it, it may still be certified. Obviously that piece was made years ago, but GREENGUARD requires quarterly and annual testing on a representative product for all product categories that have certification. So find out if they still have certification on the product, this would show that they have had consistently low-emitting materials over a long time - which should help you with your case for a credit. Also - even if you don't get the credit, try and unwrap the furniture from its shipping material as sometimes the material that it is shipped in (cardboard) can act like a sponge and therefore keep the potentially bad VOCs, which should off-gas and dissipate, around for a while. Good luck.