Yeah - I would love to see pics of them too! Regarding determining the value of parts, I'll offer up the following that may help:
On eBay, you can search and see completed listings. And eBay keeps the completed listings on the site for quite some time, so there is a decent span of time to look through. To get to them, click on advanced on the top right here (I highlighted yellow):
On the next screen, click the check box for "completed listings":
Then, if you haven't put in search words up above, do so and click the search button. Scan the results for results that ended with items sold as opposed to just expired.
No NOS 240z fenders there, but this can be helpful to get some transaction data points between buyers and sellers which are recent for many items. eBay has hefty fees for the seller. So, you may want to keep in mind that the final sale price is not what the seller gets. I sold a NOS dashboard a year or so ago on eBay for around $1400 US. The fees to eBay were something like 14%. Ridiculous. So, I avoid selling anything on eBay if I can.
Also, shipping can be very expensive unless you get a discount through a business (like your workplace) that gets good rates. That shipping cost, almost always paid for by the buyer, is included in the buyers valuation. So, if something has a market value of $1000, but costs $500 to ship, then that buyer is not likely to spend more than $500 for the item regardless of the $1000 value. A buyer that can pick it up without shipping, on the other hand will likely pay the $1000 value.