Are you sure this is a legitimate offer? this sounds an awful lot like an appraisal scam. If i were you i would accept the offer, as this is a pretty good offer for this name which you'd regret not having accepted (if you don't have any personl development plans) but if the offer maker asks you to first get it appraised at a site suggested by him then don't waste your time and money and walk away.
I highly doubt it's a legit offer. This name would be lucky to sell for reg fee IMO. Sounds like potentially a domain appraisal scam. Have they asked for a domain appraisal yet? Might want to read this just incase: http://www.domainappraisalscam.com/page.cfm/id/14655