If you are looking for a good general guide of used equipment values you might want to try Equipment Guru - based out of Northr California. They collect data based on UCC filings, etc. You can contact them at: website eqguru.com, tele 800.300.8890. Don't really now anyone that publishes retail pricing on new equipment. By the way it ain't free.
The forklift industry is relatively low volume industry compared to the auto industry. In a very good year there are about 200,000 new units of all types sold and about 25% of those are low lift pallet type units.
The "Blue Book" and like publications are no more than structured depreciation schedules. They do not appear to consider desireability of the equipment and do not adequately
address the overall condition of the equipment. As most used equipment managers know, some units are almost worthless even in good condition (for various reasons) and others hold their values extremely well for a very long time.
Therefore, your options are somewhat limited. Either call and get other trusted opinions or have a lot of experience.